87 lines
2.8 KiB
JavaScript
87 lines
2.8 KiB
JavaScript
/* Fetch */
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// vim: set ts=2 sw=2 et tw=80:
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const BODY_METHODS = ['PUT', 'POST', 'PATCH'];
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const NON_BODY_METHODS = ['GET', 'OPTIONS', 'HEAD', 'DELETE'];
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const METHODS = BODY_METHODS + NON_BODY_METHODS;
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/**
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* @function doFetchRequest
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* @param {String} method The method of the Fetch request. One of: 'GET',
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* 'POST', 'PUT', 'DELETE', 'PATCH', 'OPTIONS', 'HEAD'
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* @param {String} url The url of the API to call, optionally with parameters.
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* @param {Object} headers The Associative Array containing the Request Headers.
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* It must be undefined if there are no headers.
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* @param {String} body The body String to be sent to the server. It must be
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* undefined if there is no body.
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* @returns {Promise} which receives the HTTP response.
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*/
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function doFetchRequest(method, url, headers, body) {
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if (METHODS.indexOf(method) == -1) {
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throw new Error(`${method} is not a method`);
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return;
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}
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if (BODY_METHODS.indexOf(method) != -1 && typeof body != 'string') {
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throw new Error(`body must be a string with ${BODY_METHODS}`);
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return;
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} else if (NON_BODY_METHODS.indexOf(method) != -1 && body !== undefined) {
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throw new Error(`body must be undefined with ${NON_BODY_METHODS}`);
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return;
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}
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return fetch(url, {
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method: method,
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headers: headers,
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body: body
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});
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}
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/** @function doJSONRequest
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* @param {String} method The method of the Fetch request. One of: 'GET',
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* 'POST', 'PUT', 'DELETE'.
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* @param {String} url The url of the API to call, optionally with parameters.
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* @param {Object} headers The Associative Array containing the Request Headers.
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* It must be undefined if there are no headers.
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* @param {Object} data The object to be sent as JSON body to the server.
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* It must be undefined if there is no body.
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* @returns {Promise} which receives directly the object parsed from the
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* response JSON.
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*/
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function doJSONRequest(method, url, headers, data){
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const JSON_MIME = 'application/json';
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headers = Object.assign({}, headers);
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if (('Content-Type' in headers && headers['Content-Type'] !== JSON_MIME) ||
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('Accept' in headers && headers['Accept'] !== JSON_MIME)) {
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throw new Error(`headers object contains Content-Type or Accept`);
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return;
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}
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headers['Accept'] = JSON_MIME;
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if (NON_BODY_METHODS.indexOf(method) != -1 && data !== undefined) {
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throw new Error(`data must be undefined with ${NON_BODY_METHODS}`);
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return;
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} else if (BODY_METHODS.indexOf(method) != -1) {
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if (typeof data != 'object' || data === null) {
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throw new Error(`data must be a non-null object with ${BODY_METHODS}`);
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return;
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}
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try {
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data = JSON.stringify(data);
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} catch (e) {
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throw new Error('data cannot be converted into JSON: ' + e);
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return;
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}
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headers['Content-Type'] = JSON_MIME;
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}
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return doFetchRequest(method, url, headers, data).then(res => res.json());
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}
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