MOBILE-2253 core: Implement HTTP interceptor for WS calls

src/app/app.module.ts

@@ -15,7 +15,7 @@
 import { BrowserModule } from '@angular/platform-browser';
 import { ErrorHandler, NgModule } from '@angular/core';
 import { IonicApp, IonicErrorHandler, IonicModule, Platform } from 'ionic-angular';
-import { HttpClient, HttpClientModule } from '@angular/common/http';
+import { HttpClient, HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
 
 import { SplashScreen } from '@ionic-native/splash-screen';
 import { StatusBar } from '@ionic-native/status-bar';
@@ -25,6 +25,7 @@ import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
 import { TranslateHttpLoader } from '@ngx-translate/http-loader';
 
 import { MyApp } from './app.component';
+import { CoreInterceptor } from '../classes/interceptor';
 import { CoreLoggerProvider } from '../providers/logger';
 import { CoreDbProvider } from '../providers/db';
 import { CoreAppProvider } from '../providers/app';
@@ -80,6 +81,11 @@ export function createTranslateLoader(http: HttpClient) {
         MyApp
     ],
     providers: [
+        {
+            provide: HTTP_INTERCEPTORS,
+            useClass: CoreInterceptor,
+            multi: true,
+        },
         StatusBar,
         SplashScreen,
         SQLite,

src/classes/interceptor.ts

@@ -0,0 +1,79 @@
+// (C) Copyright 2015 Martin Dougiamas
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { Injectable } from '@angular/core';
+import { HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';
+import { Observable } from 'rxjs';
+
+/**
+ * Interceptor for Http calls. Adds the header 'Content-Type'='application/x-www-form-urlencoded'
+ * and serializes the parameters if needed.
+ */
+@Injectable()
+export class CoreInterceptor implements HttpInterceptor {
+
+    constructor() {}
+
+    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<any> {
+        // Add the header and serialize the body if needed.
+        const newReq = req.clone({
+            headers: req.headers.set('Content-Type', 'application/x-www-form-urlencoded'),
+            body: typeof req.body == 'object' && String(req.body) != '[object File]' ?
+                    CoreInterceptor.serialize(req.body) : req.body
+        });
+
+        // Pass on the cloned request instead of the original request.
+        return next.handle(newReq);
+    }
+
+    /**
+     * Serialize an object to be used in a request.
+     *
+     * @param {any} obj Object to serialize.
+     * @param {boolean} [addNull] Add null values to the serialized as empty parameters.
+     * @return {string} Serialization of the object.
+     */
+    public static serialize(obj: any, addNull?: boolean) : string {
+        let query = '',
+            fullSubName,
+            subValue,
+            innerObj;
+
+        for (let name in obj) {
+            let value = obj[name];
+
+            if (value instanceof Array) {
+                for (let i = 0; i < value.length; ++i) {
+                    subValue = value[i];
+                    fullSubName = name + '[' + i + ']';
+                    innerObj = {};
+                    innerObj[fullSubName] = subValue;
+                    query += this.serialize(innerObj) + '&';
+                }
+            } else if (value instanceof Object) {
+                for (let subName in value) {
+                    subValue = value[subName];
+                    fullSubName = name + '[' + subName + ']';
+                    innerObj = {};
+                    innerObj[fullSubName] = subValue;
+                    query += this.serialize(innerObj) + '&';
+                }
+            } else if (addNull || (typeof value != 'undefined' && value !== null)) {
+                query += encodeURIComponent(name) + '=' + encodeURIComponent(value) + '&';
+            }
+        }
+
+        return query.length ? query.substr(0, query.length - 1) : query;
+    }
+}

src/providers/utils/utils.ts

@@ -1036,46 +1036,6 @@ export class CoreUtilsProvider {
         return value1 === value2;
     }
 
-    /**
-     * Serialize an object to be used in a request.
-     *
-     * @param {any} obj Object to serialize.
-     * @param {boolean} [addNull] Add null values to the serialized as empty parameters.
-     * @return {string} Serialization of the object.
-     */
-    serialize(obj: any, addNull?: boolean) : string {
-        let query = '',
-            fullSubName,
-            subValue,
-            innerObj;
-
-        for (let name in obj) {
-            let value = obj[name];
-
-            if (value instanceof Array) {
-                for (let i = 0; i < value.length; ++i) {
-                    subValue = value[i];
-                    fullSubName = name + '[' + i + ']';
-                    innerObj = {};
-                    innerObj[fullSubName] = subValue;
-                    query += this.serialize(innerObj) + '&';
-                }
-            } else if (value instanceof Object) {
-                for (let subName in value) {
-                    subValue = value[subName];
-                    fullSubName = name + '[' + subName + ']';
-                    innerObj = {};
-                    innerObj[fullSubName] = subValue;
-                    query += this.serialize(innerObj) + '&';
-                }
-            } else if (addNull || (typeof value != 'undefined' && value !== null)) {
-                query += encodeURIComponent(name) + '=' + encodeURIComponent(value) + '&';
-            }
-        }
-
-        return query.length ? query.substr(0, query.length - 1) : query;
-    }
-
     /**
      * Stringify an object, sorting the properties. It doesn't sort arrays, only object properties. E.g.:
      * {b: 2, a: 1} -> '{"a":1,"b":2}'

src/providers/ws.ts

@@ -24,6 +24,7 @@ import { CoreTextUtilsProvider } from './utils/text';
 import { CoreUtilsProvider } from './utils/utils';
 import { CoreConstants } from '../core/constants';
 import { Md5 } from 'ts-md5/dist/md5';
+import { CoreInterceptor } from '../classes/interceptor';
 
 /**
  * Interface of the presets accepted by the WS call.
@@ -416,7 +417,7 @@ export class CoreWSProvider {
      */
     protected getQueueItemId(method: string, url: string, params?: any) : string {
         if (params) {
-            url += '###' + this.utils.serialize(params);
+            url += '###' + CoreInterceptor.serialize(params);
         }
         return method + '#' + Md5.hashAsciiStr(url);
     }
@@ -595,7 +596,7 @@ export class CoreWSProvider {
         siteUrl = preSets.siteUrl + '/webservice/rest/server.php?moodlewsrestformat=json';
 
         // Serialize data.
-        data = this.utils.serialize(data);
+        data = CoreInterceptor.serialize(data);
 
         // Perform sync request using XMLHttpRequest.
         xhr = new (<any>window).XMLHttpRequest();