1 files changed, 109 insertions, 0 deletions
diff --git a/src/server/apis/google/GoogleApiServerUtils.ts b/src/server/apis/google/GoogleApiServerUtils.ts
new file mode 100644
index 000000000..817b2b696
--- /dev/null
+++ b/src/server/apis/google/GoogleApiServerUtils.ts
@@ -0,0 +1,109 @@
+import { google, docs_v1 } from "googleapis";
+import { createInterface } from "readline";
+import { readFile, writeFile } from "fs";
+import { OAuth2Client } from "google-auth-library";
+
+/**
+ * Server side authentication for Google Api queries.
+ */
+export namespace GoogleApiServerUtils {
+
+    // If modifying these scopes, delete token.json.
+    const prefix = 'https://www.googleapis.com/auth/';
+    const SCOPES = [
+        'documents.readonly',
+        'documents',
+        'drive',
+        'drive.file',
+    ];
+    // The file token.json stores the user's access and refresh tokens, and is
+    // created automatically when the authorization flow completes for the first
+    // time.
+    export const parseBuffer = (data: Buffer) => JSON.parse(data.toString());
+
+    export namespace Docs {
+
+        export interface CredentialPaths {
+            credentials: string;
+            token: string;
+        }
+
+        export type Endpoint = docs_v1.Docs;
+
+        export const GetEndpoint = async (paths: CredentialPaths) => {
+            return new Promise<Endpoint>((resolve, reject) => {
+                readFile(paths.credentials, (err, credentials) => {
+                    if (err) {
+                        reject(err);
+                        return console.log('Error loading client secret file:', err);
+                    }
+                    return authorize(parseBuffer(credentials), paths.token).then(auth => {
+                        resolve(google.docs({ version: "v1", auth }));
+                    });
+                });
+            });
+        };
+
+    }
+
+    /**
+     * Create an OAuth2 client with the given credentials, and returns the promise resolving to the authenticated client
+     * @param {Object} credentials The authorization client credentials.
+     */
+    export function authorize(credentials: any, token_path: string): Promise<OAuth2Client> {
+        const { client_secret, client_id, redirect_uris } = credentials.installed;
+        const oAuth2Client = new google.auth.OAuth2(
+            client_id, client_secret, redirect_uris[0]);
+
+        return new Promise<OAuth2Client>((resolve, reject) => {
+            readFile(token_path, (err, token) => {
+                // Check if we have previously stored a token.
+                if (err) {
+                    return getNewToken(oAuth2Client, token_path).then(resolve, reject);
+                }
+                oAuth2Client.setCredentials(parseBuffer(token));
+                resolve(oAuth2Client);
+            });
+        });
+    }
+
+    /**
+     * Get and store new token after prompting for user authorization, and then
+     * execute the given callback with the authorized OAuth2 client.
+     * @param {google.auth.OAuth2} oAuth2Client The OAuth2 client to get token for.
+     * @param {getEventsCallback} callback The callback for the authorized client.
+     */
+    function getNewToken(oAuth2Client: OAuth2Client, token_path: string) {
+        return new Promise<OAuth2Client>((resolve, reject) => {
+            const authUrl = oAuth2Client.generateAuthUrl({
+                access_type: 'offline',
+                scope: SCOPES.map(relative => prefix + relative),
+            });
+            console.log('Authorize this app by visiting this url:', authUrl);
+            const rl = createInterface({
+                input: process.stdin,
+                output: process.stdout,
+            });
+            rl.question('Enter the code from that page here: ', (code) => {
+                rl.close();
+                oAuth2Client.getToken(code, (err, token) => {
+                    if (err || !token) {
+                        reject(err);
+                        return console.error('Error retrieving access token', err);
+                    }
+                    oAuth2Client.setCredentials(token);
+                    // Store the token to disk for later program executions
+                    writeFile(token_path, JSON.stringify(token), (err) => {
+                        if (err) {
+                            console.error(err);
+                            reject(err);
+                        }
+                        console.log('Token stored to', token_path);
+                    });
+                    resolve(oAuth2Client);
+                });
+            });
+        });
+    }
+
+}
+\ No newline at end of file