more complete DB abstractions

10 files changed, 489 insertions, 431 deletions

diff --git a/extension/background/db.js b/extension/background/db.js
index d9bff8fee..0e4576851 100644
--- a/extension/background/db.js
+++ b/extension/background/db.js
@@ -47,3 +47,30 @@ function openTalerDb() {
         };
     });
 }
+function exportDb(db) {
+    let dump = {
+        name: db.name,
+        version: db.version,
+        stores: {}
+    };
+    return new Promise((resolve, reject) => {
+        let tx = db.transaction(db.objectStoreNames);
+        tx.addEventListener('complete', (e) => {
+            resolve(dump);
+        });
+        for (let i = 0; i < db.objectStoreNames.length; i++) {
+            let name = db.objectStoreNames[i];
+            let storeDump = {};
+            dump.stores[name] = storeDump;
+            let store = tx.objectStore(name)
+                .openCursor()
+                .addEventListener('success', (e) => {
+                let cursor = e.target.result;
+                if (cursor) {
+                    storeDump[cursor.key] = cursor.value;
+                    cursor.continue();
+                }
+            });
+        }
+    });
+}
diff --git a/extension/background/db.ts b/extension/background/db.ts
index 92fff47f8..1dd399907 100644
--- a/extension/background/db.ts
+++ b/extension/background/db.ts
@@ -56,7 +56,7 @@ namespace Db {
     mintBaseUrl: string;
     coinValue: AmountJson;
   }
-  
+
   export interface Coin {
     coinPub: string;
     coinPriv: string;
@@ -88,19 +88,51 @@ function openTalerDb(): Promise<IDBDatabase> {
     };
     req.onupgradeneeded = (e) => {
       let db = req.result;
-      console.log ("DB: upgrade needed: oldVersion = " + e.oldVersion);
+      console.log("DB: upgrade needed: oldVersion = " + e.oldVersion);
       switch (e.oldVersion) {
         case 0: // DB does not exist yet
-          let mints = db.createObjectStore("mints", { keyPath: "baseUrl" });
+          let mints = db.createObjectStore("mints", {keyPath: "baseUrl"});
           mints.createIndex("pubKey", "keys.master_public_key");
-          db.createObjectStore("reserves", { keyPath: "reserve_pub"});
-          db.createObjectStore("denoms", { keyPath: "denomPub" });
-          let coins = db.createObjectStore("coins", { keyPath: "coinPub" });
+          db.createObjectStore("reserves", {keyPath: "reserve_pub"});
+          db.createObjectStore("denoms", {keyPath: "denomPub"});
+          let coins = db.createObjectStore("coins", {keyPath: "coinPub"});
           coins.createIndex("mintBaseUrl", "mintBaseUrl");
-          db.createObjectStore("transactions", { keyPath: "contractHash" });
-          db.createObjectStore("precoins", { keyPath: "coinPub", autoIncrement: true });
+          db.createObjectStore("transactions", {keyPath: "contractHash"});
+          db.createObjectStore("precoins",
+                               {keyPath: "coinPub", autoIncrement: true});
           break;
       }
     };
   });
 }
+
+
+function exportDb(db): Promise<any> {
+  let dump = {
+    name: db.name,
+    version: db.version,
+    stores: {}
+  };
+
+  return new Promise((resolve, reject) => {
+
+    let tx = db.transaction(db.objectStoreNames);
+    tx.addEventListener('complete', (e) => {
+      resolve(dump);
+    });
+    for (let i = 0; i < db.objectStoreNames.length; i++) {
+      let name = db.objectStoreNames[i];
+      let storeDump = {};
+      dump.stores[name] = storeDump;
+      let store = tx.objectStore(name)
+                    .openCursor()
+                    .addEventListener('success', (e) => {
+                      let cursor = e.target.result;
+                      if (cursor) {
+                        storeDump[cursor.key] = cursor.value;
+                        cursor.continue();
+                      }
+                    });
+    }
+  });
+}
\ No newline at end of file
diff --git a/extension/background/http.ts b/extension/background/http.ts
index da0360dfe..9a064e974 100644
--- a/extension/background/http.ts
+++ b/extension/background/http.ts
@@ -14,6 +14,8 @@
  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
  */
 
+"use strict";
+
 interface HttpResponse {
   status: number;
   responseText: string;
@@ -55,8 +57,13 @@ function httpGet(url: string|uri.URI) {
 }
 
 
-function httpPost(url: string|uri.URI, body) {
-  return httpReq("put", url, {req: JSON.stringify(body)});
+function httpPostJson(url: string|uri.URI, body) {
+  return httpReq("post", url, {req: JSON.stringify(body)});
+}
+
+
+function httpPostForm(url: string|uri.URI, form) {
+  return httpReq("post", url, {req: form});
 }
 
 
diff --git a/extension/background/messaging.ts b/extension/background/messaging.ts
new file mode 100644
index 000000000..fc513bd04
--- /dev/null
+++ b/extension/background/messaging.ts
@@ -0,0 +1,72 @@
+/*
+ This file is part of TALER
+ (C) 2016 GNUnet e.V.
+
+ TALER is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
+ */
+
+
+/**
+ * Messaging for the WebExtensions wallet.  Should contain
+ * parts that are specific for WebExtensions, but as little business
+ * logic as possible.
+ * @module Messaging
+ * @author Florian Dold
+ */
+
+"use strict";
+
+let handlers = {
+  ["balances"]: function(db, detail, sendResponse) {
+    getBalances(db).then(sendResponse);
+    return true;
+  },
+  ["dump-db"]: function(db, detail, sendResponse) {
+    exportDb(db).then(sendResponse);
+    return true;
+  },
+  ["reset-db"]: function(db, detail, sendResponse) {
+    let tx = db.transaction(db.objectStoreNames, 'readwrite');
+    for (let i = 0; i < db.objectStoreNames.length; i++) {
+      tx.objectStore(db.objectStoreNames[i]).clear();
+    }
+    indexedDB.deleteDatabase(DB_NAME);
+    chrome.browserAction.setBadgeText({text: ""});
+    console.log("reset done");
+    // Response is synchronous
+    return false;
+  },
+  ["confirm-reserve"]: function(db, detail, sendResponse) {
+    return confirmReserveHandler(db, detail, sendResponse);
+  }
+};
+
+
+function wxMain() {
+  chrome.browserAction.setBadgeText({text: ""});
+
+  openTalerDb().then((db) => {
+    updateBadge(db);
+    chrome.runtime.onMessage.addListener(
+      function(req, sender, onresponse) {
+        if (req.type in handlers) {
+          return handlers[req.type](db, req.detail, onresponse);
+        }
+        console.error(format("Request type {1} unknown, req {0}",
+                             JSON.stringify(req),
+                             req.type));
+        return false;
+      });
+  });
+}
+
+wxMain();
\ No newline at end of file
diff --git a/extension/background/query.ts b/extension/background/query.ts
index bfe3102f3..1a61c66ca 100644
--- a/extension/background/query.ts
+++ b/extension/background/query.ts
@@ -1,6 +1,6 @@
 /*
  This file is part of TALER
- (C) 2015 GNUnet e.V.
+ (C) 2016 GNUnet e.V.
 
  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU General Public License as published by the Free Software
@@ -16,50 +16,147 @@
 
 /// <reference path="../decl/chrome/chrome.d.ts" />
 
-"use strict";
 
+/**
+ * Database query abstractions.
+ * @module Query
+ * @author Florian Dold
+ */
+
+"use strict";
 
 function Query(db) {
   return new QueryRoot(db);
 }
 
-class QueryStream  {
-  qr: QueryRoot;
-  storeName;
-  constructor(qr, storeName) {
-    this.qr = qr;
-    this.storeName = storeName;
+
+abstract class QueryStreamBase {
+  abstract subscribe(f: (isDone: boolean, value: any) => void);
+  root: QueryRoot;
+
+  constructor(root: QueryRoot) {
+    this.root = root;
   }
-  join(indexName: string, key: any) {
+
+  indexJoin(storeName: string, indexName: string, key: any): QueryStreamBase {
     // join on the source relation's key, which may be
     // a path or a transformer function
-    throw Error("Not implemented");
+    return new QueryStreamIndexJoin(this, storeName, indexName, key);
+  }
+
+  filter(f: (any) => boolean): QueryStreamBase {
+    return new QueryStreamFilter(this, f);
   }
-  reduce(f, acc): Promise<any> {
+
+  reduce(f, acc?): Promise<any> {
     let leakedResolve;
     let p = new Promise((resolve, reject) => {
       leakedResolve = resolve;
     });
-    let qr = this.qr;
-    let storeName = this.storeName;
 
-    function doReduce() {
-      let req = qr.tx.objectStore(storeName).openCursor();
+    this.subscribe((isDone, value) => {
+      if (isDone) {
+        leakedResolve(acc);
+        return;
+      }
+      acc = f(value, acc);
+    });
+
+    return Promise.resolve().then(() => this.root.finish().then(() => p));
+  }
+}
+
+
+class QueryStreamFilter extends QueryStreamBase {
+  s: QueryStreamBase;
+  filterFn;
+
+  constructor(s: QueryStreamBase, filterFn) {
+    super(s.root);
+    this.s = s;
+    this.filterFn = filterFn;
+  }
+
+  subscribe(f) {
+    this.s.subscribe((isDone, value) => {
+      if (isDone) {
+        f(true, undefined);
+        return;
+      }
+      if (this.filterFn(value)) {
+        f(false, value)
+      }
+    });
+  }
+}
+
+
+class QueryStreamIndexJoin extends QueryStreamBase {
+  s: QueryStreamBase;
+  storeName;
+  key;
+  constructor(s, storeName: string, indexName: string, key: any) {
+    super(s.root);
+    this.s = s;
+    this.storeName = storeName;
+    this.key = key;
+  }
+
+  subscribe(f) {
+    this.s.subscribe((isDone, value) => {
+      if (isDone) {
+        f(true, undefined);
+        return;
+      }
+
+      let s = this.root.tx.objectStore(this.storeName);
+      let req = s.openCursor(IDBKeyRange.only(value));
+      req.onsuccess = () => {
+        let cursor = req.result;
+        if (cursor) {
+          f(false, [value, cursor.value]);
+          cursor.continue();
+        } else {
+          f(true, undefined);
+        }
+      }
+    });
+  }
+
+}
+
+
+class IterQueryStream extends QueryStreamBase {
+  private qr: QueryRoot;
+  private storeName;
+  private options;
+
+  constructor(qr, storeName, options?) {
+    super(qr);
+    this.qr = qr;
+    this.options = options;
+    this.storeName = storeName;
+  }
+
+  subscribe(f) {
+    function doIt() {
+      let s = this.qr.tx.objectStore(this.storeName);
+      let kr = undefined;
+      if (this.options && ("only" in this.options)) {
+        kr = IDBKeyRange.only(this.options.only);
+      }
+      let req = s.openCursor(kr);
       req.onsuccess = (e) => {
         let cursor: IDBCursorWithValue = req.result;
         if (cursor) {
-          acc = f(acc, cursor.value);
+          f(false, cursor.value);
           cursor.continue();
         } else {
-          leakedResolve(acc);
+          f(true, undefined);
         }
       }
     }
-
-    this.qr.work.push(doReduce);
-    // We need this one level of indirection so that the kickoff
-    // is run asynchronously.
-    return Promise.resolve().then(() => this.qr.finish().then(() => p));
+    this.qr.work.push(doIt.bind(this));
   }
 }
 
@@ -75,9 +172,14 @@ class QueryRoot {
     this.db = db;
   }
 
-  iter(storeName): QueryStream {
+  iter(storeName): QueryStreamBase {
+    this.stores.add(storeName);
+    return new IterQueryStream(this, storeName);
+  }
+
+  iterOnly(storeName, key): QueryStreamBase {
     this.stores.add(storeName);
-    return new QueryStream(this, storeName);
+    return new IterQueryStream(this, storeName, {only: key});
   }
 
   put(storeName, val): QueryRoot {
diff --git a/extension/background/timerThread.js b/extension/background/timerThread.js
index 7ac66a711..7ade360f3 100644
--- a/extension/background/timerThread.js
+++ b/extension/background/timerThread.js
@@ -7,4 +7,4 @@
 
 onmessage = function(e) {
   self.setInterval(() => postMessage(true), e.data.interval);
-}
+};
\ No newline at end of file
diff --git a/extension/background/wallet.js b/extension/background/wallet.js
index e97e34028..971da7195 100644
--- a/extension/background/wallet.js
+++ b/extension/background/wallet.js
@@ -84,86 +84,65 @@ function signDeposit(db, offer, cds) {
  * @param allowedMints
  */
 function getPossibleMintCoins(db, paymentAmount, depositFeeLimit, allowedMints) {
-    return new Promise((resolve, reject) => {
-        let m = {};
-        let found = false;
-        let tx = db.transaction(["mints", "coins"]);
-        // First pass: Get all coins from acceptable mints.
-        for (let info of allowedMints) {
-            let req_mints = tx.objectStore("mints")
-                .index("pubKey")
-                .get(info.master_pub);
-            req_mints.onsuccess = (e) => {
-                let mint = req_mints.result;
-                if (!mint) {
-                    // We don't have that mint ...
-                    return;
-                }
-                let req_coins = tx.objectStore("coins")
-                    .index("mintBaseUrl")
-                    .openCursor(IDBKeyRange.only(mint.baseUrl));
-                req_coins.onsuccess = (e) => {
-                    let cursor = req_coins.result;
-                    if (!cursor) {
-                        return;
-                    }
-                    let value = cursor.value;
-                    let cd = {
-                        coin: cursor.value,
-                        denom: mint.keys.denoms.find((e) => e.denom_pub === value.denomPub)
-                    };
-                    if (!cd.denom) {
-                        throw Error("denom not found (database inconsistent)");
-                    }
-                    let x = m[mint.baseUrl];
-                    if (!x) {
-                        m[mint.baseUrl] = [cd];
-                    }
-                    else {
-                        x.push(cd);
-                    }
-                    cursor.continue();
-                };
-            };
+    let m = {};
+    function storeMintCoin(mc) {
+        let mint = mc[0];
+        let coin = mc[1];
+        let cd = {
+            coin: coin,
+            denom: mint.keys.denoms.find((e) => e.denom_pub === coin.denomPub)
+        };
+        if (!cd.denom) {
+            throw Error("denom not found (database inconsistent)");
         }
-        tx.oncomplete = (e) => {
-            let ret = {};
-            nextMint: for (let key in m) {
-                let coins = m[key].map((x) => ({
-                    a: new Amount(x.denom.fee_deposit),
-                    c: x
-                }));
-                // Sort by ascending deposit fee
-                coins.sort((o1, o2) => o1.a.cmp(o2.a));
-                let maxFee = new Amount(depositFeeLimit);
-                let minAmount = new Amount(paymentAmount);
-                let accFee = new Amount(coins[0].c.denom.fee_deposit);
-                let accAmount = Amount.getZero(coins[0].c.coin.currentAmount.currency);
-                let usableCoins = [];
-                nextCoin: for (let i = 0; i < coins.length; i++) {
-                    let coinAmount = new Amount(coins[i].c.coin.currentAmount);
-                    let coinFee = coins[i].a;
-                    if (coinAmount.cmp(coinFee) <= 0) {
-                        continue nextCoin;
-                    }
-                    accFee.add(coinFee);
-                    accAmount.add(coinAmount);
-                    if (accFee.cmp(maxFee) >= 0) {
-                        console.log("too much fees");
-                        continue nextMint;
-                    }
-                    usableCoins.push(coins[i].c);
-                    if (accAmount.cmp(minAmount) >= 0) {
-                        ret[key] = usableCoins;
-                        continue nextMint;
-                    }
+        let x = m[mint.baseUrl];
+        if (!x) {
+            m[mint.baseUrl] = [cd];
+        }
+        else {
+            x.push(cd);
+        }
+    }
+    let ps = allowedMints.map((info) => {
+        return Query(db)
+            .iterOnly("mints", info.master_pub)
+            .indexJoin("coins", "mintBaseUrl", (mint) => mint.baseUrl)
+            .reduce(storeMintCoin);
+    });
+    return Promise.all(ps).then(() => {
+        let ret = {};
+        nextMint: for (let key in m) {
+            let coins = m[key].map((x) => ({
+                a: new Amount(x.denom.fee_deposit),
+                c: x
+            }));
+            // Sort by ascending deposit fee
+            coins.sort((o1, o2) => o1.a.cmp(o2.a));
+            let maxFee = new Amount(depositFeeLimit);
+            let minAmount = new Amount(paymentAmount);
+            let accFee = new Amount(coins[0].c.denom.fee_deposit);
+            let accAmount = Amount.getZero(coins[0].c.coin.currentAmount.currency);
+            let usableCoins = [];
+            nextCoin: for (let i = 0; i < coins.length; i++) {
+                let coinAmount = new Amount(coins[i].c.coin.currentAmount);
+                let coinFee = coins[i].a;
+                if (coinAmount.cmp(coinFee) <= 0) {
+                    continue nextCoin;
+                }
+                accFee.add(coinFee);
+                accAmount.add(coinAmount);
+                if (accFee.cmp(maxFee) >= 0) {
+                    console.log("too much fees");
+                    continue nextMint;
+                }
+                usableCoins.push(coins[i].c);
+                if (accAmount.cmp(minAmount) >= 0) {
+                    ret[key] = usableCoins;
+                    continue nextMint;
                 }
             }
-            resolve(ret);
-        };
-        tx.onerror = (e) => {
-            reject();
-        };
+        }
+        return ret;
     });
 }
 function executePay(db, offer, payCoinInfo, merchantBaseUrl, chosenMint) {
@@ -187,13 +166,12 @@ function executePay(db, offer, payCoinInfo, merchantBaseUrl, chosenMint) {
         .putAll("coins", payCoinInfo.map((pci) => pci.updatedCoin))
         .finish();
 }
-function confirmPay(db, detail, sendResponse) {
+function confirmPayHandler(db, detail, sendResponse) {
     let offer = detail.offer;
     getPossibleMintCoins(db, offer.contract.amount, offer.contract.max_fee, offer.contract.mints)
         .then((mcs) => {
         if (Object.keys(mcs).length == 0) {
             sendResponse({ error: "Not enough coins." });
-            // FIXME: does not work like expected here ...
             return;
         }
         let mintUrl = Object.keys(mcs)[0];
@@ -207,7 +185,7 @@ function confirmPay(db, detail, sendResponse) {
     });
     return true;
 }
-function doPayment(db, detail, sendResponse) {
+function doPaymentHandler(db, detail, sendResponse) {
     let H_contract = detail.H_contract;
     Query(db)
         .get("transactions", H_contract)
@@ -225,7 +203,7 @@ function doPayment(db, detail, sendResponse) {
     // async sendResponse
     return true;
 }
-function confirmReserve(db, detail, sendResponse) {
+function confirmReserveHandler(db, detail, sendResponse) {
     let reservePriv = EddsaPrivateKey.create();
     let reservePub = reservePriv.getPublicKey();
     let form = new FormData();
@@ -234,55 +212,47 @@ function confirmReserve(db, detail, sendResponse) {
     form.append(detail.field_reserve_pub, reservePub.toCrock());
     form.append(detail.field_mint, detail.mint);
     // XXX: set bank-specified fields.
-    let myRequest = new XMLHttpRequest();
-    myRequest.open('post', detail.post_url);
-    myRequest.send(form);
     let mintBaseUrl = canonicalizeBaseUrl(detail.mint);
-    myRequest.addEventListener('readystatechange', (e) => {
-        if (myRequest.readyState == XMLHttpRequest.DONE) {
-            // TODO: extract as interface
-            let resp = {
-                status: myRequest.status,
-                text: myRequest.responseText,
-                success: undefined,
-                backlink: undefined
-            };
-            let reserveRecord = {
-                reserve_pub: reservePub.toCrock(),
-                reserve_priv: reservePriv.toCrock(),
-                mint_base_url: mintBaseUrl,
-                created: now,
-                last_query: null,
-                current_amount: null,
-                // XXX: set to actual amount
-                initial_amount: null
-            };
-            // XXX: insert into db.
-            switch (myRequest.status) {
-                case 200:
-                    resp.success = true;
-                    // We can't show the page directly, so
-                    // we show some generic page from the wallet.
-                    resp.backlink = chrome.extension.getURL("pages/reserve-success.html");
-                    let tx = db.transaction(['reserves'], 'readwrite');
-                    tx.objectStore('reserves').add(reserveRecord);
-                    tx.addEventListener('complete', (e) => {
-                        console.log('tx complete, pk was ' + reserveRecord.reserve_pub);
-                        sendResponse(resp);
-                        var mint;
-                        updateMintFromUrl(db, reserveRecord.mint_base_url)
-                            .then((m) => {
-                            mint = m;
-                            return updateReserve(db, reservePub, mint);
-                        })
-                            .then((reserve) => depleteReserve(db, reserve, mint));
-                    });
-                    break;
-                default:
-                    resp.success = false;
-                    sendResponse(resp);
-            }
+    httpPostForm(detail.post_url, form)
+        .then((hresp) => {
+        // TODO: extract as interface
+        let resp = {
+            status: hresp.status,
+            text: hresp.responseText,
+            success: undefined,
+            backlink: undefined
+        };
+        let reserveRecord = {
+            reserve_pub: reservePub.toCrock(),
+            reserve_priv: reservePriv.toCrock(),
+            mint_base_url: mintBaseUrl,
+            created: now,
+            last_query: null,
+            current_amount: null,
+            // XXX: set to actual amount
+            initial_amount: null
+        };
+        if (hresp.status != 200) {
+            resp.success = false;
+            return resp;
         }
+        resp.success = true;
+        // We can't show the page directly, so
+        // we show some generic page from the wallet.
+        // TODO: this should not be webextensions-specific
+        resp.backlink = chrome.extension.getURL("pages/reserve-success.html");
+        return Query(db)
+            .put("reserves", reserveRecord)
+            .finish()
+            .then(() => {
+            // Do this in the background
+            updateMintFromUrl(db, reserveRecord.mint_base_url)
+                .then((mint) => {
+                updateReserve(db, reservePub, mint)
+                    .then((reserve) => depleteReserve(db, reserve, mint));
+            });
+            return resp;
+        });
     });
     // Allow async response
     return true;
@@ -345,7 +315,7 @@ function withdrawExecute(db, pc) {
         wd.reserve_sig = pc.withdrawSig;
         wd.coin_ev = pc.coinEv;
         let reqUrl = URI("reserve/withdraw").absoluteTo(r.mint_base_url);
-        return httpPost(reqUrl, wd);
+        return httpPostJson(reqUrl, wd);
     })
         .then(resp => {
         if (resp.status != 200) {
@@ -368,7 +338,7 @@ function withdrawExecute(db, pc) {
     });
 }
 function updateBadge(db) {
-    function countNonEmpty(n, c) {
+    function countNonEmpty(c, n) {
         if (c.currentAmount.fraction != 0 || c.currentAmount.value != 0) {
             return n + 1;
         }
@@ -449,8 +419,10 @@ function updateReserve(db, reservePub, mint) {
                 throw Error();
             }
             reserve.current_amount = reserveInfo.balance;
-            let q = Query(db);
-            return q.put("reserves", reserve).finish().then(() => reserve);
+            return Query(db)
+                .put("reserves", reserve)
+                .finish()
+                .then(() => reserve);
         });
     });
 }
@@ -476,45 +448,7 @@ function updateMintFromUrl(db, baseUrl) {
         return Query(db).put("mints", mint).finish().then(() => mint);
     });
 }
-function dumpDb(db, detail, sendResponse) {
-    let dump = {
-        name: db.name,
-        version: db.version,
-        stores: {}
-    };
-    let tx = db.transaction(db.objectStoreNames);
-    tx.addEventListener('complete', (e) => {
-        sendResponse(dump);
-    });
-    for (let i = 0; i < db.objectStoreNames.length; i++) {
-        let name = db.objectStoreNames[i];
-        let storeDump = {};
-        dump.stores[name] = storeDump;
-        let store = tx.objectStore(name)
-            .openCursor()
-            .addEventListener('success', (e) => {
-            let cursor = e.target.result;
-            if (cursor) {
-                storeDump[cursor.key] = cursor.value;
-                cursor.continue();
-            }
-        });
-    }
-    return true;
-}
-// Just for debugging.
-function reset(db, detail, sendResponse) {
-    let tx = db.transaction(db.objectStoreNames, 'readwrite');
-    for (let i = 0; i < db.objectStoreNames.length; i++) {
-        tx.objectStore(db.objectStoreNames[i]).clear();
-    }
-    indexedDB.deleteDatabase(DB_NAME);
-    chrome.browserAction.setBadgeText({ text: "" });
-    console.log("reset done");
-    // Response is synchronous
-    return false;
-}
-function balances(db, detail, sendResponse) {
+function getBalances(db) {
     function collectBalances(c, byCurrency) {
         let acc = byCurrency[c.currentAmount.currency];
         if (!acc) {
@@ -523,32 +457,9 @@ function balances(db, detail, sendResponse) {
         let am = new Amount(c.currentAmount);
         am.add(new Amount(acc));
         byCurrency[c.currentAmount.currency] = am.toJson();
+        return byCurrency;
     }
-    Query(db)
+    return Query(db)
         .iter("coins")
-        .reduce(collectBalances, {})
-        .then(sendResponse);
-    return true;
-}
-function wxMain() {
-    chrome.browserAction.setBadgeText({ text: "" });
-    openTalerDb().then((db) => {
-        updateBadge(db);
-        chrome.runtime.onMessage.addListener(function (req, sender, onresponse) {
-            let dispatch = {
-                "confirm-reserve": confirmReserve,
-                "confirm-pay": confirmPay,
-                "dump-db": dumpDb,
-                "balances": balances,
-                "execute-payment": doPayment,
-                "reset": reset
-            };
-            if (req.type in dispatch) {
-                return dispatch[req.type](db, req.detail, onresponse);
-            }
-            console.error(format("Request type {1} unknown, req {0}", JSON.stringify(req), req.type));
-            return false;
-        });
-    });
+        .reduce(collectBalances, {});
 }
-wxMain();
diff --git a/extension/background/wallet.ts b/extension/background/wallet.ts
index 4ca4eb802..b3593f682 100644
--- a/extension/background/wallet.ts
+++ b/extension/background/wallet.ts
@@ -176,90 +176,72 @@ function getPossibleMintCoins(db: IDBDatabase,
                               paymentAmount: AmountJson,
                               depositFeeLimit: AmountJson,
                               allowedMints: MintInfo[]): Promise<MintCoins> {
-  return new Promise((resolve, reject) => {
-    let m: MintCoins = {};
-    let found = false;
-    let tx = db.transaction(["mints", "coins"]);
-    // First pass: Get all coins from acceptable mints.
-    for (let info of allowedMints) {
-      let req_mints = tx.objectStore("mints")
-                        .index("pubKey")
-                        .get(info.master_pub);
-      req_mints.onsuccess = (e) => {
-        let mint: Db.Mint = req_mints.result;
-        if (!mint) {
-          // We don't have that mint ...
-          return;
-        }
-        let req_coins = tx.objectStore("coins")
-                          .index("mintBaseUrl")
-                          .openCursor(IDBKeyRange.only(mint.baseUrl));
-        req_coins.onsuccess = (e) => {
-          let cursor: IDBCursorWithValue = req_coins.result;
-          if (!cursor) {
-            return;
-          }
-          let value: Db.Coin = cursor.value;
-          let cd = {
-            coin: cursor.value,
-            denom: mint.keys.denoms.find((e) => e.denom_pub === value.denomPub)
-          };
-          if (!cd.denom) {
-            throw Error("denom not found (database inconsistent)");
-          }
-          let x = m[mint.baseUrl];
-          if (!x) {
-            m[mint.baseUrl] = [cd];
-          } else {
-            x.push(cd);
-          }
-          cursor.continue();
-        }
-      }
-    }
 
-    tx.oncomplete = (e) => {
-      let ret: MintCoins = {};
-
-      nextMint:
-        for (let key in m) {
-          let coins = m[key].map((x) => ({
-            a: new Amount(x.denom.fee_deposit),
-            c: x
-          }));
-          // Sort by ascending deposit fee
-          coins.sort((o1, o2) => o1.a.cmp(o2.a));
-          let maxFee = new Amount(depositFeeLimit);
-          let minAmount = new Amount(paymentAmount);
-          let accFee = new Amount(coins[0].c.denom.fee_deposit);
-          let accAmount = Amount.getZero(coins[0].c.coin.currentAmount.currency);
-          let usableCoins: Db.CoinWithDenom[] = [];
-          nextCoin:
-            for (let i = 0; i < coins.length; i++) {
-              let coinAmount = new Amount(coins[i].c.coin.currentAmount);
-              let coinFee = coins[i].a;
-              if (coinAmount.cmp(coinFee) <= 0) {
-                continue nextCoin;
-              }
-              accFee.add(coinFee);
-              accAmount.add(coinAmount);
-              if (accFee.cmp(maxFee) >= 0) {
-                console.log("too much fees");
-                continue nextMint;
-              }
-              usableCoins.push(coins[i].c);
-              if (accAmount.cmp(minAmount) >= 0) {
-                ret[key] = usableCoins;
-                continue nextMint;
-              }
-            }
-        }
-      resolve(ret);
-    };
 
-    tx.onerror = (e) => {
-      reject();
+  let m: MintCoins = {};
+
+  function storeMintCoin(mc) {
+    let mint = mc[0];
+    let coin = mc[1];
+    let cd = {
+      coin: coin,
+      denom: mint.keys.denoms.find((e) => e.denom_pub === coin.denomPub)
+    };
+    if (!cd.denom) {
+      throw Error("denom not found (database inconsistent)");
     }
+    let x = m[mint.baseUrl];
+    if (!x) {
+      m[mint.baseUrl] = [cd];
+    } else {
+      x.push(cd);
+    }
+  }
+
+  let ps = allowedMints.map((info) => {
+    return Query(db)
+      .iterOnly("mints", info.master_pub)
+      .indexJoin("coins", "mintBaseUrl", (mint) => mint.baseUrl)
+      .reduce(storeMintCoin);
+  });
+
+  return Promise.all(ps).then(() => {
+    let ret: MintCoins = {};
+
+    nextMint:
+      for (let key in m) {
+        let coins = m[key].map((x) => ({
+          a: new Amount(x.denom.fee_deposit),
+          c: x
+        }));
+        // Sort by ascending deposit fee
+        coins.sort((o1, o2) => o1.a.cmp(o2.a));
+        let maxFee = new Amount(depositFeeLimit);
+        let minAmount = new Amount(paymentAmount);
+        let accFee = new Amount(coins[0].c.denom.fee_deposit);
+        let accAmount = Amount.getZero(coins[0].c.coin.currentAmount.currency);
+        let usableCoins: Db.CoinWithDenom[] = [];
+        nextCoin:
+          for (let i = 0; i < coins.length; i++) {
+            let coinAmount = new Amount(coins[i].c.coin.currentAmount);
+            let coinFee = coins[i].a;
+            if (coinAmount.cmp(coinFee) <= 0) {
+              continue nextCoin;
+            }
+            accFee.add(coinFee);
+            accAmount.add(coinAmount);
+            if (accFee.cmp(maxFee) >= 0) {
+              console.log("too much fees");
+              continue nextMint;
+            }
+            usableCoins.push(coins[i].c);
+            if (accAmount.cmp(minAmount) >= 0) {
+              ret[key] = usableCoins;
+              continue nextMint;
+            }
+          }
+      }
+    return ret;
   });
 }
 
@@ -292,7 +274,7 @@ function executePay(db,
 }
 
 
-function confirmPay(db, detail: ConfirmPayRequest, sendResponse) {
+function confirmPayHandler(db, detail: ConfirmPayRequest, sendResponse) {
   let offer: Offer = detail.offer;
   getPossibleMintCoins(db,
                        offer.contract.amount,
@@ -301,7 +283,6 @@ function confirmPay(db, detail: ConfirmPayRequest, sendResponse) {
     .then((mcs) => {
       if (Object.keys(mcs).length == 0) {
         sendResponse({error: "Not enough coins."});
-        // FIXME: does not work like expected here ...
         return;
       }
       let mintUrl = Object.keys(mcs)[0];
@@ -317,7 +298,7 @@ function confirmPay(db, detail: ConfirmPayRequest, sendResponse) {
 }
 
 
-function doPayment(db, detail, sendResponse) {
+function doPaymentHandler(db, detail, sendResponse) {
   let H_contract = detail.H_contract;
   Query(db)
     .get("transactions", H_contract)
@@ -337,7 +318,7 @@ function doPayment(db, detail, sendResponse) {
 }
 
 
-function confirmReserve(db, detail, sendResponse) {
+function confirmReserveHandler(db, detail, sendResponse) {
   let reservePriv = EddsaPrivateKey.create();
   let reservePub = reservePriv.getPublicKey();
   let form = new FormData();
@@ -346,16 +327,13 @@ function confirmReserve(db, detail, sendResponse) {
   form.append(detail.field_reserve_pub, reservePub.toCrock());
   form.append(detail.field_mint, detail.mint);
   // XXX: set bank-specified fields.
-  let myRequest = new XMLHttpRequest();
-  myRequest.open('post', detail.post_url);
-  myRequest.send(form);
   let mintBaseUrl = canonicalizeBaseUrl(detail.mint);
-  myRequest.addEventListener('readystatechange', (e) => {
-    if (myRequest.readyState == XMLHttpRequest.DONE) {
+  httpPostForm(detail.post_url, form)
+    .then((hresp) => {
       // TODO: extract as interface
       let resp = {
-        status: myRequest.status,
-        text: myRequest.responseText,
+        status: hresp.status,
+        text: hresp.responseText,
         success: undefined,
         backlink: undefined
       };
@@ -369,33 +347,31 @@ function confirmReserve(db, detail, sendResponse) {
         // XXX: set to actual amount
         initial_amount: null
       };
-      // XXX: insert into db.
-      switch (myRequest.status) {
-        case 200:
-          resp.success = true;
-          // We can't show the page directly, so
-          // we show some generic page from the wallet.
-          resp.backlink = chrome.extension.getURL("pages/reserve-success.html");
-          let tx = db.transaction(['reserves'], 'readwrite');
-          tx.objectStore('reserves').add(reserveRecord);
-          tx.addEventListener('complete', (e) => {
-            console.log('tx complete, pk was ' + reserveRecord.reserve_pub);
-            sendResponse(resp);
-            var mint;
-            updateMintFromUrl(db, reserveRecord.mint_base_url)
-              .then((m) => {
-                mint = m;
-                return updateReserve(db, reservePub, mint);
-              })
-              .then((reserve) => depleteReserve(db, reserve, mint));
-          });
-          break;
-        default:
-          resp.success = false;
-          sendResponse(resp);
+
+      if (hresp.status != 200) {
+        resp.success = false;
+        return resp;
       }
-    }
-  });
+
+      resp.success = true;
+      // We can't show the page directly, so
+      // we show some generic page from the wallet.
+      // TODO: this should not be webextensions-specific
+      resp.backlink = chrome.extension.getURL("pages/reserve-success.html");
+      return Query(db)
+        .put("reserves", reserveRecord)
+        .finish()
+        .then(() => {
+          // Do this in the background
+          updateMintFromUrl(db, reserveRecord.mint_base_url)
+            .then((mint) => {
+              updateReserve(db, reservePub, mint)
+                .then((reserve) => depleteReserve(db, reserve, mint));
+            });
+          return resp;
+        });
+    });
+
   // Allow async response
   return true;
 }
@@ -473,7 +449,7 @@ function withdrawExecute(db, pc: Db.PreCoin): Promise<Db.Coin> {
       wd.reserve_sig = pc.withdrawSig;
       wd.coin_ev = pc.coinEv;
       let reqUrl = URI("reserve/withdraw").absoluteTo(r.mint_base_url);
-      return httpPost(reqUrl, wd);
+      return httpPostJson(reqUrl, wd);
     })
     .then(resp => {
       if (resp.status != 200) {
@@ -500,7 +476,7 @@ function withdrawExecute(db, pc: Db.PreCoin): Promise<Db.Coin> {
 
 
 function updateBadge(db) {
-  function countNonEmpty(n, c) {
+  function countNonEmpty(c, n) {
     if (c.currentAmount.fraction != 0 || c.currentAmount.value != 0) {
       return n + 1;
     }
@@ -595,8 +571,10 @@ function updateReserve(db: IDBDatabase,
           throw Error();
         }
         reserve.current_amount = reserveInfo.balance;
-        let q = Query(db);
-        return q.put("reserves", reserve).finish().then(() => reserve);
+        return Query(db)
+          .put("reserves", reserve)
+          .finish()
+          .then(() => reserve);
       });
     });
 }
@@ -626,49 +604,7 @@ function updateMintFromUrl(db, baseUrl) {
 }
 
 
-function dumpDb(db, detail, sendResponse) {
-  let dump = {
-    name: db.name,
-    version: db.version,
-    stores: {}
-  };
-  let tx = db.transaction(db.objectStoreNames);
-  tx.addEventListener('complete', (e) => {
-    sendResponse(dump);
-  });
-  for (let i = 0; i < db.objectStoreNames.length; i++) {
-    let name = db.objectStoreNames[i];
-    let storeDump = {};
-    dump.stores[name] = storeDump;
-    let store = tx.objectStore(name)
-                  .openCursor()
-                  .addEventListener('success', (e) => {
-                    let cursor = e.target.result;
-                    if (cursor) {
-                      storeDump[cursor.key] = cursor.value;
-                      cursor.continue();
-                    }
-                  });
-  }
-  return true;
-}
-
-
-// Just for debugging.
-function reset(db, detail, sendResponse) {
-  let tx = db.transaction(db.objectStoreNames, 'readwrite');
-  for (let i = 0; i < db.objectStoreNames.length; i++) {
-    tx.objectStore(db.objectStoreNames[i]).clear();
-  }
-  indexedDB.deleteDatabase(DB_NAME);
-  chrome.browserAction.setBadgeText({text: ""});
-  console.log("reset done");
-  // Response is synchronous
-  return false;
-}
-
-
-function balances(db, detail, sendResponse): boolean {
+function getBalances(db): Promise<any> {
   function collectBalances(c: Db.Coin, byCurrency) {
     let acc: AmountJson = byCurrency[c.currentAmount.currency];
     if (!acc) {
@@ -677,41 +613,10 @@ function balances(db, detail, sendResponse): boolean {
     let am = new Amount(c.currentAmount);
     am.add(new Amount(acc));
     byCurrency[c.currentAmount.currency] = am.toJson();
+    return byCurrency;
   }
 
-  Query(db)
+  return Query(db)
     .iter("coins")
-    .reduce(collectBalances, {})
-    .then(sendResponse);
-  return true;
+    .reduce(collectBalances, {});
 }
-
-
-function wxMain() {
-  chrome.browserAction.setBadgeText({text: ""});
-
-  openTalerDb().then((db) => {
-    updateBadge(db);
-    chrome.runtime.onMessage.addListener(
-      function(req, sender, onresponse) {
-        let dispatch = {
-          "confirm-reserve": confirmReserve,
-          "confirm-pay": confirmPay,
-          "dump-db": dumpDb,
-          "balances": balances,
-          "execute-payment": doPayment,
-          "reset": reset
-        };
-        if (req.type in dispatch) {
-          return dispatch[req.type](db, req.detail, onresponse);
-        }
-        console.error(format("Request type {1} unknown, req {0}",
-                             JSON.stringify(req),
-                             req.type));
-        return false;
-      });
-  });
-}
-
-
-wxMain();
\ No newline at end of file
diff --git a/extension/manifest.json b/extension/manifest.json
index 0c30edfd7..478c2a9b0 100644
--- a/extension/manifest.json
+++ b/extension/manifest.json
@@ -47,6 +47,7 @@
       "background/emscriptif.js",
       "background/db.js",
       "background/query.js",
+      "background/messaging.js",
       "background/http.js",
       "background/wallet.js"
     ]
diff --git a/extension/tsconfig.json b/extension/tsconfig.json
index 565924b43..2b88688d9 100644
--- a/extension/tsconfig.json
+++ b/extension/tsconfig.json
@@ -9,6 +9,7 @@
       "background/db.ts",
       "background/query.ts",
       "background/http.ts",
+      "background/messaging.ts",
       "lib/util.ts",
       "lib/polyfill-react.ts",
       "content_scripts/notify.ts",