From 27e007f2dd1141f67bf29b1ad2f684a222101693 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niccol=C3=B2=20Belli?= <niccolo.belli@linuxsystems.it>
Date: Sun, 11 Jun 2017 19:45:18 +0200
Subject: [PATCH] Step 17.17: Create facebook Meteor service

---
 api/server/services/facebook.ts | 104 ++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 api/server/services/facebook.ts

diff --git a/api/server/services/facebook.ts b/api/server/services/facebook.ts
new file mode 100644
index 000000000..072d7860a
--- /dev/null
+++ b/api/server/services/facebook.ts
@@ -0,0 +1,104 @@
+import {Users} from "../collections/users";
+import {FB} from "fb";
+
+export interface FbProfile {
+  name?: string;
+  pictureUrl?: string;
+};
+
+export class FacebookService {
+  private APP_ID: string = Meteor.settings.private.oAuth.facebook.appId;
+  private APP_SECRET: string = Meteor.settings.private.oAuth.facebook.secret;
+
+  constructor() {
+  }
+
+  async getAppToken(): Promise<string> {
+    try {
+      return (await FB.api(`/oauth/access_token?client_id=${this.APP_ID}&client_secret=${this.APP_SECRET}&grant_type=client_credentials`)).access_token;
+    } catch (e) {
+      throw new Meteor.Error('cannot-receive', 'Cannot get an app token');
+    }
+  }
+
+//TODO: create a before.insert in the users collection to check if the token is valid
+  async tokenIsValid(token: string): Promise<boolean> {
+    try {
+      return (await FB.api(`debug_token?input_token=${token}&access_token=${await this.getAppToken()}`)).data.is_valid;
+    } catch (e) {
+      console.error(e);
+      return false;
+    }
+  }
+
+// Useless because we already got a long lived token
+  async getLongLivedToken(token: string): Promise<string> {
+    try {
+      return (await FB.api(`/oauth/access_token?grant_type=fb_exchange_token&client_id=${this.APP_ID}&client_secret=${this.APP_SECRET}&fb_exchange_token=${token}`)).access_token;
+    } catch (e) {
+      throw new Meteor.Error('cannot-receive', 'Cannot get a long lived token');
+    }
+  }
+
+  async getAccessToken(user: string): Promise<string> {
+    //TODO: check if token has expired, if so the user must login again
+    try {
+      const facebook = await Users.findOne(user).services.facebook;
+      if (facebook.accessToken) {
+        return facebook.accessToken;
+      } else {
+        throw new Error();
+      }
+    } catch (e) {
+      throw new Meteor.Error('unauthorized', 'User must be logged-in with Facebook to call this method');
+    }
+  }
+
+  async getFriends(accessToken: string, user?: string): Promise<any> {
+    //TODO: check if more permissions are needed, if so user must login again
+    try {
+      const params: any = {
+        //fields: 'id,name',
+        limit: 5000
+      };
+      let friends: string[] = [];
+      let result: any;
+      const fb = FB.withAccessToken(accessToken);
+
+      do {
+        result = await fb.api(`/${user || 'me'}/friends`, params);
+        friends = friends.concat(result.data);
+        params.after = result.paging && result.paging.cursors && result.paging.cursors.after;
+      } while (result.paging && result.paging.next);
+
+      return friends;
+    } catch (e) {
+      console.error(e);
+      throw new Meteor.Error('cannot-receive', 'Cannot get friends')
+    }
+  }
+
+  async getProfile(accessToken: string, user?: string): Promise<FbProfile> {
+    //TODO: check if more permissions are needed, if so user must login again
+    try {
+      const params: any = {
+        fields: 'id,name,picture.width(800).height(800)'
+      };
+
+      let profile: FbProfile = {};
+
+      const fb = FB.withAccessToken(accessToken);
+      const result = await fb.api(`/${user || 'me'}`, params);
+
+      profile.name = result.name;
+      profile.pictureUrl = result.picture.data.url;
+
+      return profile;
+    } catch (e) {
+      console.error(e);
+      throw new Meteor.Error('cannot-receive', 'Cannot get profile')
+    }
+  }
+}
+
+export const facebookService = new FacebookService();