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JavaScript - HTTP and Fetch API helper
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| export const Status = { | |
| Ok: 200, | |
| Unassigned: 299, | |
| BadRequest: 400, | |
| Unauthorized: 401, | |
| NotFound: 404, | |
| }; | |
| export const Methods = { | |
| Get: "GET", | |
| Post: "POST", | |
| Put: "PUT", | |
| Delete: "DELETE", | |
| }; | |
| export const Headers = { | |
| Accept: "application/json", | |
| "Content-Type": "application/json", | |
| }; | |
| export const AuthorizationType = { | |
| Bearer: "bearer ", | |
| Basic: "basic " | |
| } | |
| export const Credentials = { | |
| SameOrigin: "same-origin", /* default */ | |
| Include: "include", | |
| Omit: "omit" | |
| } | |
| export const addAuthorization = (headers, type, value) => { | |
| headers["Authorization"] = `${type}${value}`; | |
| } | |
| class HttpHelper { | |
| static post = (url, body) => { | |
| return fetch(url, { | |
| method: Methods.Post, | |
| /*credentials: Credentials.Include,*/ | |
| headers: Headers, | |
| body: JSON.stringify(body), | |
| }) | |
| .then(this.handleResponse) | |
| .catch(this.handleUnexpectedError); | |
| }; | |
| static get = (url, query) => { | |
| if (query) | |
| url += "?" + new URLSearchParams(query).toString(); | |
| return fetch(url, { | |
| method: Methods.Get, | |
| /*credentials: Credentials.Include,*/ | |
| headers: Headers | |
| }) | |
| .then(this.handleResponse) | |
| .catch(this.handleUnexpectedError); | |
| }; | |
| static handleResponse = (response) => { | |
| const headers = this.readHeaders(response.headers); | |
| if (this.isError(response)) | |
| return this.handleExpectedError(response, headers); | |
| return response.json().then((body) => { | |
| return new AppResponse(body, headers); | |
| }); | |
| /*In case of issue with empty responses use .text() instead of .json()*/ | |
| /*Same thing to do for handleExpectedError*/ | |
| // return response.text().then((bodyText) => { | |
| // let body = bodyText ? JSON.parse(bodyText) : {}; | |
| // return new AppResponse(body, headers); | |
| // }); | |
| }; | |
| static handleExpectedError = (error, headers) => { | |
| /*Expected (Unhandled exceptions if treated to 500)*/ | |
| /*See : https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch*/ | |
| return error.json().then((body) => { | |
| switch (error.status) { | |
| case Status.BadRequest: | |
| return Promise.reject(new BadRequestError(body, headers)); | |
| case Status.Unauthorized: | |
| return Promise.reject(new UnauthorizedError(body, headers)); | |
| case Status.NotFound: | |
| return Promise.reject(new NotFoundError(body, headers)); | |
| default: | |
| return Promise.reject(new AppError(body, headers)); | |
| } | |
| }); | |
| }; | |
| static handleUnexpectedError = (error) => { | |
| /*Unexpected: Server offline, Network down, Unhandled exceptions*/ | |
| /*return need to be rejected again*/ | |
| if (!(error instanceof AppError)) | |
| return Promise.reject(new AppError(error)); | |
| /*handleExpectedError return will get here*/ | |
| return Promise.reject(error); | |
| }; | |
| static isError = (response) => { | |
| return response.status < Status.Ok || response.status > Status.Unassigned; | |
| }; | |
| static readHeaders = (headers) => { | |
| let headersObject = {}; | |
| headers.forEach((value, key) => { | |
| headersObject[key] = value; | |
| }); | |
| return headersObject; | |
| }; | |
| } | |
| export default HttpHelper; | |
| export class AppResponse { | |
| constructor(body = null, headers = null) { | |
| this.body = body; | |
| this.headers = headers; | |
| } | |
| } | |
| export class AppError { | |
| constructor(body = null, headers = null) { | |
| this.body = body; | |
| this.headers = headers; | |
| } | |
| } | |
| export class NotFoundError extends AppError { | |
| constructor(body = null, headers = null) { | |
| super(body, headers); | |
| } | |
| } | |
| export class BadRequestError extends AppError { | |
| constructor(body = null, headers = null) { | |
| super(body, headers); | |
| } | |
| } | |
| export class UnauthorizedError extends AppError { | |
| constructor(body = null, headers = null) { | |
| super(body, headers); | |
| } | |
| } |
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