httpsnippet.ts

import { map as eventStreamMap } from 'event-stream';
import FormData from 'form-data/lib/form_data';
import { Param, PostDataCommon, Request as NpmHarRequest } from 'har-format';
import { validateRequest } from 'har-validator-compiled';
import { stringify as queryStringify } from 'querystring';
import { format as urlFormat, parse as urlParse, UrlWithParsedQuery } from 'url';

import { formDataIterator, isBlob } from './helpers/form-data';
import { getHeaderName } from './helpers/headers';
import { ReducedHelperObject, reducer } from './helpers/reducer';
import { ClientId, TargetId, targets } from './targets/targets';

export { availableTargets, extname } from './helpers/utils';
export { addTarget, addTargetClient } from './targets/targets';

// We're implementing the logic for which FormData object to use, ourselves.
// This allows us to use the native FormData object in the browser and the `form-data` module in Node,
// instead of relying on the package entrypoint to handle that.
const resolveFormData =
 // @ts-expect-error — we're only using window.FormData if it exists
 typeof window !== 'undefined' && window.FormData ? window.FormData : FormData;

const DEBUG_MODE = false;

const debug = {
 // eslint-disable-next-line @typescript-eslint/no-empty-function -- intentional noop
 info: DEBUG_MODE ? console.info : () => {},
};

/** is this wrong? yes. according to the spec (http://www.softwareishard.com/blog/har-12-spec/#postData) it's technically wrong since `params` and `text` are (by the spec) mutually exclusive. However, in practice, this is not what is often the case.
 *
 * In general, this library takes a _descriptive_ rather than _perscriptive_ approach (see https://amyrey.web.unc.edu/classes/ling-101-online/tutorials/understanding-prescriptive-vs-descriptive-grammar/).
 *
 * Then, in addition to that, it really adds to complexity with TypeScript (TypeScript takes this constraint very very seriously) in a way that's not actually super useful. So, we treat this object as though it could have both or either of `params` and/or `text`.
 */
type PostDataBase = PostDataCommon & {
 text?: string;
 params?: Param[];
};

export type HarRequest = Omit<NpmHarRequest, 'postData'> & { postData: PostDataBase };

export interface RequestExtras {
 postData: PostDataBase & {
 jsonObj?: ReducedHelperObject;
 paramsObj?: ReducedHelperObject;
 boundary?: string;
 };
 fullUrl: string;
 queryObj: ReducedHelperObject;
 headersObj: ReducedHelperObject;
 uriObj: UrlWithParsedQuery;
 cookiesObj: ReducedHelperObject;
 allHeaders: ReducedHelperObject;
}

export type Request = HarRequest & RequestExtras;

interface Entry {
 request: Partial<HarRequest>;
}

export interface HarEntry {
 log: {
 version: string;
 creator: {
 name: string;
 version: string;
 };
 entries: Entry[];
 };
}

export const isHarEntry = (value: any): value is HarEntry =>
 typeof value === 'object' &&
 'log' in value &&
 typeof value.log === 'object' &&
 'entries' in value.log &&
 Array.isArray(value.log.entries);

export class HTTPSnippet {
 requests: Request[] = [];

 constructor(input: HarEntry | HarRequest) {
 let entries: Entry[] = [];

 // prep the main container
 this.requests = [];

 // is it har?
 if (isHarEntry(input)) {
 entries = input.log.entries;
 } else {
 entries = [
 {
 request: input,
 },
 ];
 }

 entries.forEach(({ request }) => {
 // add optional properties to make validation successful
 const req = {
 bodySize: 0,
 headersSize: 0,
 headers: [],
 cookies: [],
 httpVersion: 'HTTP/1.1',
 queryString: [],
 ...request,
 postData: request?.postData || {
 mimeType: request.postData?.mimeType || 'application/octet-stream',
 },
 };

 if (validateRequest(req)) {
 this.requests.push(this.prepare(req));
 }
 });
 }

 prepare = (harRequest: HarRequest) => {
 const request: Request = {
 ...harRequest,
 fullUrl: '',
 uriObj: {} as UrlWithParsedQuery,
 queryObj: {},
 headersObj: {},
 cookiesObj: {},
 allHeaders: {},
 };

 // construct query objects
 if (request.queryString && request.queryString.length) {
 debug.info('queryString found, constructing queryString pair map');

 request.queryObj = request.queryString.reduce(reducer, {});
 }

 // construct headers objects
 if (request.headers && request.headers.length) {
 const http2VersionRegex = /^HTTP\/2/;
 request.headersObj = request.headers.reduce((accumulator, { name, value }) => {
 const headerName = http2VersionRegex.exec(request.httpVersion)
 ? name.toLocaleLowerCase()
 : name;
 return {
 ...accumulator,
 [headerName]: value,
 };
 }, {});
 }

 // construct headers objects
 if (request.cookies && request.cookies.length) {
 request.cookiesObj = request.cookies.reduceRight(
 (accumulator, { name, value }) => ({
 ...accumulator,
 [name]: value,
 }),
 {},
 );
 }

 // construct Cookie header
 const cookies = request.cookies?.map(
 ({ name, value }) => `${encodeURIComponent(name)}=${encodeURIComponent(value)}`,
 );

 if (cookies?.length) {
 request.allHeaders.cookie = cookies.join('; ');
 }

 switch (request?.postData.mimeType) {
 case 'multipart/mixed':
 case 'multipart/related':
 case 'multipart/form-data':
 case 'multipart/alternative':
 // reset values
 request.postData.text = '';
 request.postData.mimeType = 'multipart/form-data';

 if (request.postData?.params) {
 const form = new resolveFormData();

 // The `form-data` module returns one of two things: a native FormData object, or its own polyfill
 // Since the polyfill does not support the full API of the native FormData object, when this library is running in a browser environment it'll fail on two things:
 //
 // 1. The API for `form.append()` has three arguments and the third should only be present when the second is a
 // Blob or USVString.
 // 1. `FormData.pipe()` isn't a function.
 //
 // Since the native FormData object is iterable, we easily detect what version of `form-data` we're working with here to allow `multipart/form-data` requests to be compiled under both browser and Node environments.
 //
 // This hack is pretty awful but it's the only way we can use this library in the browser as if we code this against just the native FormData object, we can't polyfill that back into Node because Blob and File objects, which something like `formdata-polyfill` requires, don't exist there.
 const isNativeFormData = typeof form[Symbol.iterator] === 'function';

 // TODO: THIS ABSOLUTELY MUST BE REMOVED.
 // IT BREAKS SOME USE-CASES FOR MULTIPART FORMS THAT DEPEND ON BEING ABLE TO SET THE BOUNDARY.
 // easter egg
 const boundary = '---011000010111000001101001'; // this is binary for "api". yep.
 if (!isNativeFormData) {
 form._boundary = boundary;
 }

 request.postData?.params.forEach(param => {
 const name = param.name;
 const value = param.value || '';
 const filename = param.fileName || null;

 if (isNativeFormData) {
 if (isBlob(value)) {
 form.append(name, value, filename);
 } else {
 form.append(name, value);
 }
 } else {
 form.append(name, value, {
 filename,
 contentType: param.contentType || null,
 });
 }
 });

 if (isNativeFormData) {
 for (const data of formDataIterator(form, boundary)) {
 request.postData.text += data;
 }
 } else {
 form.pipe(
 // @ts-expect-error TODO
 eventStreamMap(data => {
 request.postData.text += data;
 }),
 );
 }

 request.postData.boundary = boundary;

 // Since headers are case-sensitive we need to see if there's an existing `Content-Type` header that we can override.
 const contentTypeHeader =
 getHeaderName(request.headersObj, 'content-type') || 'content-type';

 request.headersObj[contentTypeHeader] = `multipart/form-data; boundary=${boundary}`;
 }
 break;

 case 'application/x-www-form-urlencoded':
 if (!request.postData.params) {
 request.postData.text = '';
 } else {
 // @ts-expect-error the `har-format` types make this challenging
 request.postData.paramsObj = request.postData.params.reduce(reducer, {});

 // always overwrite
 request.postData.text = queryStringify(request.postData.paramsObj);
 }
 break;

 case 'text/json':
 case 'text/x-json':
 case 'application/json':
 case 'application/x-json':
 request.postData.mimeType = 'application/json';

 if (request.postData.text) {
 try {
 request.postData.jsonObj = JSON.parse(request.postData.text);
 } catch (e) {
 debug.info(e);

 // force back to `text/plain` if headers have proper content-type value, then this should also work
 request.postData.mimeType = 'text/plain';
 }
 }
 break;
 }

 // create allHeaders object
 const allHeaders = {
 ...request.allHeaders,
 ...request.headersObj,
 };

 const urlWithParsedQuery = urlParse(request.url, true, true); //?

 // query string key/value pairs in with literal querystrings containd within the url
 request.queryObj = {
 ...request.queryObj,
 ...(urlWithParsedQuery.query as ReducedHelperObject),
 }; //?

 // reset uriObj values for a clean url
 const search = queryStringify(request.queryObj);

 const uriObj = {
 ...urlWithParsedQuery,
 query: request.queryObj,
 search,
 path: search ? `${urlWithParsedQuery.pathname}?${search}` : urlWithParsedQuery.pathname,
 };

 // keep the base url clean of queryString
 const url = urlFormat({
 ...urlWithParsedQuery,
 query: null,
 search: null,
 }); //?

 const fullUrl = urlFormat({
 ...urlWithParsedQuery,
 ...uriObj,
 }); //?

 return {
 ...request,
 allHeaders,
 fullUrl,
 url,
 uriObj,
 };
 };

 convert = (targetId: TargetId, clientId?: ClientId, options?: any) => {
 if (!options && clientId) {
 options = clientId;
 }

 const target = targets[targetId];
 if (!target) {
 return false;
 }

 const { convert } = target.clientsById[clientId || target.info.default];
 const results = this.requests.map(request => convert(request, options));
 return results.length === 1 ? results[0] : results;
 };
}