All: Added backend for Dropbox support

ReactNativeClient/lib/DropboxApi.js

@@ -0,0 +1,154 @@
+const { Logger } = require('lib/logger.js');
+const { shim } = require('lib/shim.js');
+const JoplinError = require('lib/JoplinError');
+const URL = require('url-parse');
+const { time } = require('lib/time-utils');
+
+class DropboxApi {
+
+	constructor(options) {
+		this.logger_ = new Logger();
+		this.options_ = options;
+		this.authToken_ = null;
+	}
+
+	setLogger(l) {
+		this.logger_ = l;
+	}
+
+	logger() {
+		return this.logger_;
+	}
+
+	authToken() {
+		return this.authToken_; // Must be "Bearer XXXXXXXXXXXXXXXXXX"
+	}
+
+	setAuthToken(v) {
+		this.authToken_ = v;
+	}
+
+	baseUrl(endPointFormat) {
+		if (['content', 'api'].indexOf(endPointFormat) < 0) throw new Error('Invalid end point format: ' + endPointFormat);
+		return 'https://' + endPointFormat + '.dropboxapi.com/2';
+	}
+
+	requestToCurl_(url, options) {
+		let output = [];
+		output.push('curl');
+		if (options.method) output.push('-X ' + options.method);
+		if (options.headers) {
+			for (let n in options.headers) {
+				if (!options.headers.hasOwnProperty(n)) continue;
+				output.push('-H ' + "'" + n + ': ' + options.headers[n] + "'");
+			}
+		}
+		if (options.body) output.push('--data ' + '"' + options.body + '"');
+		output.push(url);
+
+		return output.join(' ');		
+	}
+
+	async exec(method, path = '', body = null, headers = null, options = null) {
+		if (headers === null) headers = {};
+		if (options === null) options = {};
+		if (!options.target) options.target = 'string';
+
+		const authToken = this.authToken();
+
+		if (authToken) headers['Authorization'] = authToken;
+
+		const endPointFormat = ['files/upload', 'files/download'].indexOf(path) >= 0 ? 'content' : 'api';
+
+		if (endPointFormat === 'api') {
+			headers['Content-Type'] = 'application/json';
+			if (body && typeof body === 'object') body = JSON.stringify(body);
+		} else {
+			headers['Content-Type'] = 'application/octet-stream';
+		}
+
+		const fetchOptions = {};
+		fetchOptions.headers = headers;
+		fetchOptions.method = method;
+		if (options.path) fetchOptions.path = options.path;
+		if (body) fetchOptions.body = body;
+
+		const url = this.baseUrl(endPointFormat) + '/' + path;
+
+		let tryCount = 0;
+
+		while (true) {
+			try {
+				let response = null;
+
+				// console.info(this.requestToCurl_(url, fetchOptions));
+
+				const now = Date.now();
+				// console.info(now + ': ' + method + ' ' + url);
+
+				if (options.source == 'file' && (method == 'POST' || method == 'PUT')) {
+					response = await shim.uploadBlob(url, fetchOptions);
+				} else if (options.target == 'string') {
+					response = await shim.fetch(url, fetchOptions);
+				} else { // file
+					response = await shim.fetchBlob(url, fetchOptions);
+				}
+
+				const responseText = await response.text();
+
+				// console.info(now + ': Response: ' + responseText); 
+
+				let responseJson_ = null;
+				const loadResponseJson = () => {
+					if (!responseText) return null;
+					if (responseJson_) return responseJson_;
+					try {
+						responseJson_ = JSON.parse(responseText);
+					} catch (error) {
+						return { error: responseText };
+					}
+					return responseJson_;
+				}
+
+				// Creates an error object with as much data as possible as it will appear in the log, which will make debugging easier
+				const newError = (message) => {
+					const json = loadResponseJson();
+					let code = '';
+					if (json && json.error_summary) {
+						code = json.error_summary;
+					}
+
+					// Gives a shorter response for error messages. Useful for cases where a full HTML page is accidentally loaded instead of
+					// JSON. That way the error message will still show there's a problem but without filling up the log or screen.
+					const shortResponseText = (responseText + '').substr(0, 1024);
+					return new JoplinError(method + ' ' + path + ': ' + message + ' (' + response.status + '): ' + shortResponseText, code);
+				}
+
+				if (!response.ok) {
+					// When using fetchBlob we only get a string (not xml or json) back
+					if (options.target === 'file') throw newError('fetchBlob error');
+
+					throw newError('Error');
+				}
+
+				if (options.responseFormat === 'text') return responseText;
+
+				return loadResponseJson();
+			} catch (error) {
+				tryCount++;
+				if (error.code.indexOf('too_many_write_operations') >= 0) {
+					this.logger().warn('too_many_write_operations ' + tryCount);
+					if (tryCount >= 3) {
+						throw error;
+					}
+					await time.sleep(tryCount * 2);
+				} else {
+					throw error;
+				}
+			}
+		}
+	}
+
+}
+
+module.exports = DropboxApi;