fix(fetch): use data, form and multipart for different post data (#9248)

docs/src/api/class-fetchrequest.md

@@ -38,13 +38,11 @@ If set changes the fetch method (e.g. PUT or POST). If not specified, GET method
 
 Allows to set HTTP headers.
 
-### option: FetchRequest.fetch.data
+### option: FetchRequest.fetch.data = %%-fetch-option-data-%%
-- `data` <[string]|[Buffer]|[Serializable]>
 
-Allows to set post data of the fetch. If the data parameter is an object, it will be serialized the following way:
+### option: FetchRequest.fetch.form = %%-fetch-option-form-%%
-* If `content-type` header is set to `application/x-www-form-urlencoded` the object will be serialized as html form using `application/x-www-form-urlencoded` encoding.
+
-* If `content-type` header is set to `multipart/form-data` the object will be serialized as html form using `multipart/form-data` encoding.
+### option: FetchRequest.fetch.multipart = %%-fetch-option-multipart-%%
-* Otherwise the object will be serialized to json string and `content-type` header will be set to `application/json`.
 
 ### option: FetchRequest.fetch.timeout
 - `timeout` <[float]>
@@ -114,13 +112,11 @@ Query parameters to be send with the URL.
 
 Allows to set HTTP headers.
 
-### option: FetchRequest.post.data
+### option: FetchRequest.post.data = %%-fetch-option-data-%%
-- `data` <[string]|[Buffer]|[Serializable]>
 
-Allows to set post data of the fetch. If the data parameter is an object, it will be serialized the following way:
+### option: FetchRequest.post.form = %%-fetch-option-form-%%
-* If `content-type` header is set to `application/x-www-form-urlencoded` the object will be serialized as html form using `application/x-www-form-urlencoded` encoding.
+
-* If `content-type` header is set to `multipart/form-data` the object will be serialized as html form using `multipart/form-data` encoding.
+### option: FetchRequest.post.multipart = %%-fetch-option-multipart-%%
-* Otherwise the object will be serialized to json string and `content-type` header will be set to `application/json`.
 
 ### option: FetchRequest.post.timeout
 - `timeout` <[float]>

docs/src/api/params.md

@@ -298,6 +298,32 @@ Emulates consistent viewport for each page. Defaults to an 1280x720 viewport. Us
 Emulates consistent window screen size available inside web page via `window.screen`. Is only used when the
 [`option: viewport`] is set.
 
+## fetch-option-form
+- `form` <[Object]<[string], [string]|[float]|[boolean]>>
+
+Provides an object that will be serialized as html form using `application/x-www-form-urlencoded` encoding and sent as
+this request body. If this parameter is specified `content-type` header will be set to `application/x-www-form-urlencoded`
+unless explicitly provided.
+
+## fetch-option-multipart
+- `multipart` <[Object]<[string], [string]|[float]|[boolean]|[ReadStream]|[Object]>>
+  - `name` <[string]> File name
+  - `mimeType` <[string]> File type
+  - `buffer` <[Buffer]> File content
+
+Provides an object that will be serialized as html form using `multipart/form-data` encoding and sent as
+this request body. If this parameter is specified `content-type` header will be set to `multipart/form-data`
+unless explicitly provided. File values can be passed either as [`fs.ReadStream`](https://nodejs.org/api/fs.html#fs_class_fs_readstream)
+or as file-like object containing file name, mime-type and its content.
+
+## fetch-option-data
+- `data` <[string]|[Buffer]|[Serializable]>
+
+Allows to set post data of the request. If the data parameter is an object, it will be serialized to json string
+and `content-type` header will be set to `application/json` if not explicitly set. Otherwise the `content-type` header will be
+set to `application/octet-stream` if not explicitly set.
+
+
 ## evaluate-expression
 - `expression` <[string]>
 

src/client/fetch.ts

@@ -33,6 +33,8 @@ export type FetchOptions = {
   method?: string,
   headers?: Headers,
   data?: string | Buffer | Serializable,
+  form?: { [key: string]: string|number|boolean; };
+  multipart?: { [key: string]: string|number|boolean|fs.ReadStream|FilePayload; };
   timeout?: number,
   failOnStatusCode?: boolean,
   ignoreHTTPSErrors?: boolean,
@@ -68,16 +70,7 @@ export class FetchRequest extends ChannelOwner<channels.FetchRequestChannel, cha
     });
   }
 
-  async post(
+  async post(urlOrRequest: string | api.Request, options?: Omit<FetchOptions, 'method'>): Promise<FetchResponse> {
-    urlOrRequest: string | api.Request,
-    options?: {
-      params?: { [key: string]: string; };
-      headers?: { [key: string]: string; };
-      data?: string | Buffer | Serializable;
-      timeout?: number;
-      failOnStatusCode?: boolean;
-      ignoreHTTPSErrors?: boolean,
-    }): Promise<FetchResponse> {
     return this.fetch(urlOrRequest, {
       ...options,
       method: 'POST',
@@ -88,40 +81,46 @@ export class FetchRequest extends ChannelOwner<channels.FetchRequestChannel, cha
     return this._wrapApiCall(async (channel: channels.FetchRequestChannel) => {
       const request: network.Request | undefined = (urlOrRequest instanceof network.Request) ? urlOrRequest as network.Request : undefined;
       assert(request || typeof urlOrRequest === 'string', 'First argument must be either URL string or Request');
+      assert((options.data === undefined ? 0 : 1) + (options.form === undefined ? 0 : 1) + (options.multipart === undefined ? 0 : 1) <= 1, `Only one of 'data', 'form' or 'multipart' can be specified`);
       const url = request ? request.url() : urlOrRequest as string;
       const params = objectToArray(options.params);
       const method = options.method || request?.method();
       // Cannot call allHeaders() here as the request may be paused inside route handler.
       const headersObj = options.headers || request?.headers() ;
       const headers = headersObj ? headersObjectToArray(headersObj) : undefined;
-      let formData: any;
+      let jsonData: any;
+      let formData: channels.NameValue[] | undefined;
+      let multipartData: channels.FormField[] | undefined;
       let postDataBuffer: Buffer | undefined;
-      if (options.data) {
+      if (options.data !== undefined) {
-        if (isString(options.data)) {
+        if (isString(options.data))
           postDataBuffer = Buffer.from(options.data, 'utf8');
-        } else if (Buffer.isBuffer(options.data)) {
+        else if (Buffer.isBuffer(options.data))
           postDataBuffer = options.data;
-        } else if (typeof options.data === 'object') {
+        else if (typeof options.data === 'object')
-          formData = {};
+          jsonData = options.data;
-          // Convert file-like values to ServerFilePayload structs.
+        else
-          for (const [name, value] of Object.entries(options.data)) {
-            if (isFilePayload(value)) {
-              const payload = value as FilePayload;
-              if (!Buffer.isBuffer(payload.buffer))
-                throw new Error(`Unexpected buffer type of 'data.${name}'`);
-              formData[name] = filePayloadToJson(payload);
-            } else if (value instanceof fs.ReadStream) {
-              formData[name] = await readStreamToJson(value as fs.ReadStream);
-            } else {
-              formData[name] = value;
-            }
-          }
-        } else {
           throw new Error(`Unexpected 'data' type`);
+      } else if (options.form) {
+        formData = objectToArray(options.form);
+      } else if (options.multipart) {
+        multipartData = [];
+        // Convert file-like values to ServerFilePayload structs.
+        for (const [name, value] of Object.entries(options.multipart)) {
+          if (isFilePayload(value)) {
+            const payload = value as FilePayload;
+            if (!Buffer.isBuffer(payload.buffer))
+              throw new Error(`Unexpected buffer type of 'data.${name}'`);
+            multipartData.push({ name, file: filePayloadToJson(payload) });
+          } else if (value instanceof fs.ReadStream) {
+            multipartData.push({ name, file: await readStreamToJson(value as fs.ReadStream) });
+          } else {
+            multipartData.push({ name, value: String(value) });
+          }
         }
-        if (postDataBuffer === undefined && formData === undefined)
-          postDataBuffer = request?.postDataBuffer() || undefined;
       }
+      if (postDataBuffer === undefined && jsonData === undefined && formData === undefined && multipartData === undefined)
+        postDataBuffer = request?.postDataBuffer() || undefined;
       const postData = (postDataBuffer ? postDataBuffer.toString('base64') : undefined);
       const result = await channel.fetch({
         url,
@@ -129,7 +128,9 @@ export class FetchRequest extends ChannelOwner<channels.FetchRequestChannel, cha
         method,
         headers,
         postData,
+        jsonData,
         formData,
+        multipartData,
         timeout: options.timeout,
         failOnStatusCode: options.failOnStatusCode,
         ignoreHTTPSErrors: options.ignoreHTTPSErrors,

src/dispatchers/networkDispatchers.ts

@@ -14,13 +14,12 @@
  * limitations under the License.
  */
 
-import { Request, Response, Route, WebSocket } from '../server/network';
 import * as channels from '../protocol/channels';
-import { Dispatcher, DispatcherScope, lookupNullableDispatcher, existingDispatcher } from './dispatcher';
-import { FrameDispatcher } from './frameDispatcher';
-import { CallMetadata } from '../server/instrumentation';
 import { FetchRequest } from '../server/fetch';
-import { arrayToObject, headersArrayToObject } from '../utils/utils';
+import { CallMetadata } from '../server/instrumentation';
+import { Request, Response, Route, WebSocket } from '../server/network';
+import { Dispatcher, DispatcherScope, existingDispatcher, lookupNullableDispatcher } from './dispatcher';
+import { FrameDispatcher } from './frameDispatcher';
 
 export class RequestDispatcher extends Dispatcher<Request, channels.RequestInitializer, channels.RequestEvents> implements channels.RequestChannel {
 
@@ -186,17 +185,7 @@ export class FetchRequestDispatcher extends Dispatcher<FetchRequest, channels.Fe
   }
 
   async fetch(params: channels.FetchRequestFetchParams, metadata?: channels.Metadata): Promise<channels.FetchRequestFetchResult> {
-    const { fetchResponse, error } = await this._object.fetch({
+    const { fetchResponse, error } = await this._object.fetch(params);
-      url: params.url,
-      params: arrayToObject(params.params),
-      method: params.method,
-      headers: params.headers ? headersArrayToObject(params.headers, false) : undefined,
-      postData: params.postData ? Buffer.from(params.postData, 'base64') : undefined,
-      formData: params.formData,
-      timeout: params.timeout,
-      failOnStatusCode: params.failOnStatusCode,
-      ignoreHTTPSErrors: params.ignoreHTTPSErrors,
-    });
     let response;
     if (fetchResponse) {
       response = {

src/protocol/channels.ts

@@ -150,6 +150,16 @@ export type SerializedError = {
   value?: SerializedValue,
 };
 
+export type FormField = {
+  name: string,
+  value?: string,
+  file?: {
+    name: string,
+    mimeType: string,
+    buffer: Binary,
+  },
+};
+
 export type InterceptedResponse = {
   request: RequestChannel,
   status: number,
@@ -172,7 +182,9 @@ export type FetchRequestFetchParams = {
   method?: string,
   headers?: NameValue[],
   postData?: Binary,
-  formData?: any,
+  jsonData?: any,
+  formData?: NameValue[],
+  multipartData?: FormField[],
   timeout?: number,
   failOnStatusCode?: boolean,
   ignoreHTTPSErrors?: boolean,
@@ -182,7 +194,9 @@ export type FetchRequestFetchOptions = {
   method?: string,
   headers?: NameValue[],
   postData?: Binary,
-  formData?: any,
+  jsonData?: any,
+  formData?: NameValue[],
+  multipartData?: FormField[],
   timeout?: number,
   failOnStatusCode?: boolean,
   ignoreHTTPSErrors?: boolean,

src/protocol/protocol.yml

@@ -214,6 +214,17 @@ SerializedError:
         stack: string?
     value: SerializedValue?
 
+FormField:
+  type: object
+  properties:
+    name: string
+    value: string?
+    file:
+      type: object?
+      properties:
+        name: string
+        mimeType: string
+        buffer: binary
 
 InterceptedResponse:
   type: object
@@ -242,7 +253,13 @@ FetchRequest:
           type: array?
           items: NameValue
         postData: binary?
-        formData: json?
+        jsonData: json?
+        formData:
+          type: array?
+          items: NameValue
+        multipartData:
+          type: array?
+          items: FormField
         timeout: number?
         failOnStatusCode: boolean?
         ignoreHTTPSErrors: boolean?

src/protocol/validator.ts

@@ -147,6 +147,15 @@ export function createScheme(tChannel: (name: string) => Validator): Scheme {
     })),
     value: tOptional(tType('SerializedValue')),
   });
+  scheme.FormField = tObject({
+    name: tString,
+    value: tOptional(tString),
+    file: tOptional(tObject({
+      name: tString,
+      mimeType: tString,
+      buffer: tBinary,
+    })),
+  });
   scheme.InterceptedResponse = tObject({
     request: tChannel('Request'),
     status: tNumber,
@@ -159,7 +168,9 @@ export function createScheme(tChannel: (name: string) => Validator): Scheme {
     method: tOptional(tString),
     headers: tOptional(tArray(tType('NameValue'))),
     postData: tOptional(tBinary),
-    formData: tOptional(tAny),
+    jsonData: tOptional(tAny),
+    formData: tOptional(tArray(tType('NameValue'))),
+    multipartData: tOptional(tArray(tType('FormField'))),
     timeout: tOptional(tNumber),
     failOnStatusCode: tOptional(tBoolean),
     ignoreHTTPSErrors: tOptional(tBoolean),

src/server/fetch.ts

@@ -23,7 +23,7 @@ import zlib from 'zlib';
 import { HTTPCredentials } from '../../types/types';
 import * as channels from '../protocol/channels';
 import { TimeoutSettings } from '../utils/timeoutSettings';
-import { assert, createGuid, getPlaywrightVersion, isFilePayload, monotonicTime } from '../utils/utils';
+import { assert, createGuid, getPlaywrightVersion, monotonicTime } from '../utils/utils';
 import { BrowserContext } from './browserContext';
 import { CookieStore, domainMatches } from './cookieStore';
 import { MultipartFormData } from './formData';
@@ -32,8 +32,7 @@ import { Playwright } from './playwright';
 import * as types from './types';
 import { HeadersArray, ProxySettings } from './types';
 
-
+type FetchRequestOptions = {
-export type FetchRequestOptions = {
   userAgent: string;
   extraHTTPHeaders?: HeadersArray;
   httpCredentials?: HTTPCredentials;
@@ -84,7 +83,7 @@ export abstract class FetchRequest extends SdkObject {
     return uid;
   }
 
-  async fetch(params: types.FetchOptions): Promise<{fetchResponse?: Omit<types.FetchResponse, 'body'> & { fetchUid: string }, error?: string}> {
+  async fetch(params: channels.FetchRequestFetchParams): Promise<{fetchResponse?: Omit<types.FetchResponse, 'body'> & { fetchUid: string }, error?: string}> {
     try {
       const headers: { [name: string]: string } = {};
       const defaults = this._defaultOptions();
@@ -98,7 +97,7 @@ export abstract class FetchRequest extends SdkObject {
       }
 
       if (params.headers) {
-        for (const [name, value] of Object.entries(params.headers))
+        for (const { name, value } of params.headers)
           headers[name.toLowerCase()] = value;
       }
 
@@ -130,19 +129,17 @@ export abstract class FetchRequest extends SdkObject {
 
       const requestUrl = new URL(params.url, defaults.baseURL);
       if (params.params) {
-        for (const [name, value] of Object.entries(params.params))
+        for (const { name, value } of params.params)
           requestUrl.searchParams.set(name, value);
       }
 
       let postData;
       if (['POST', 'PUSH', 'PATCH'].includes(method))
-        postData = params.formData ? serializeFormData(params.formData, headers) : params.postData;
+        postData = serializePostData(params, headers);
-      else if (params.postData || params.formData)
+      else if (params.postData || params.jsonData || params.formData || params.multipartData)
         throw new Error(`Method ${method} does not accept post data`);
-      if (postData) {
+      if (postData)
         headers['content-length'] = String(postData.byteLength);
-        headers['content-type'] ??= 'application/octet-stream';
-      }
       const fetchResponse = await this._sendRequest(requestUrl, options, postData);
       const fetchUid = this._storeResponseBody(fetchResponse.body);
       if (params.failOnStatusCode && (fetchResponse.status < 200 || fetchResponse.status >= 400))
@@ -458,30 +455,31 @@ function parseCookie(header: string): types.NetworkCookie | null {
   return cookie;
 }
 
-function serializeFormData(data: any, headers: { [name: string]: string }): Buffer {
+function serializePostData(params: channels.FetchRequestFetchParams, headers: { [name: string]: string }): Buffer | undefined {
-  const contentType = headers['content-type'] || 'application/json';
+  assert((params.postData ? 1 : 0) + (params.jsonData ? 1 : 0) + (params.formData ? 1 : 0) + (params.multipartData ? 1 : 0) <= 1, `Only one of 'data', 'form' or 'multipart' can be specified`);
-  if (contentType === 'application/json') {
+  if (params.jsonData) {
-    const json = JSON.stringify(data);
+    const json = JSON.stringify(params.jsonData);
-    headers['content-type'] ??= contentType;
+    headers['content-type'] ??= 'application/json';
     return Buffer.from(json, 'utf8');
-  } else if (contentType === 'application/x-www-form-urlencoded') {
+  } else if (params.formData) {
     const searchParams = new URLSearchParams();
-    for (const [name, value] of Object.entries(data))
+    for (const { name, value } of params.formData)
-      searchParams.append(name, String(value));
+      searchParams.append(name, value);
+    headers['content-type'] ??= 'application/x-www-form-urlencoded';
     return Buffer.from(searchParams.toString(), 'utf8');
-  } else if (contentType === 'multipart/form-data') {
+  } else if (params.multipartData) {
     const formData = new MultipartFormData();
-    for (const [name, value] of Object.entries(data)) {
+    for (const field of params.multipartData) {
-      if (isFilePayload(value)) {
+      if (field.file)
-        const payload = value as types.FilePayload;
+        formData.addFileField(field.name, field.file);
-        formData.addFileField(name, payload);
+      else if (field.value)
-      } else if (value !== undefined) {
+        formData.addField(field.name, field.value);
-        formData.addField(name, String(value));
-      }
     }
-    headers['content-type'] = formData.contentTypeHeader();
+    headers['content-type'] ??= formData.contentTypeHeader();
     return formData.finish();
-  } else {
+  } else if (params.postData) {
-    throw new Error(`Cannot serialize data using content type: ${contentType}`);
+    headers['content-type'] ??= 'application/octet-stream';
+    return Buffer.from(params.postData, 'base64');
   }
+  return undefined;
 }

src/server/types.ts

@@ -372,30 +372,6 @@ export type SetStorageState = {
   origins?: OriginStorage[]
 };
 
-export type FileInfo = {
-  name: string,
-  mimeType?: string,
-  buffer: Buffer,
-};
-
-export type FormField = {
-  name: string,
-  value?: string,
-  file?: FileInfo,
-};
-
-export type FetchOptions = {
-  url: string,
-  params?: { [name: string]: string },
-  method?: string,
-  headers?: { [name: string]: string },
-  postData?: Buffer,
-  formData?: FormField[],
-  timeout?: number,
-  failOnStatusCode?: boolean,
-  ignoreHTTPSErrors?: boolean,
-};
-
 export type FetchResponse = {
   url: string,
   status: number,

src/utils/utils.ts

@@ -384,12 +384,12 @@ class HashStream extends stream.Writable {
   }
 }
 
-export function objectToArray(map?:  { [key: string]: string }): NameValue[] | undefined {
+export function objectToArray(map?:  { [key: string]: any }): NameValue[] | undefined {
   if (!map)
     return undefined;
   const result = [];
   for (const [name, value] of Object.entries(map))
-    result.push({ name, value });
+    result.push({ name, value: String(value) });
   return result;
 }
 

tests/browsercontext-fetch.spec.ts

@@ -726,10 +726,7 @@ it('should support application/x-www-form-urlencoded', async function({ context,
   const [req] = await Promise.all([
     server.waitForRequest('/empty.html'),
     context._request.post(server.EMPTY_PAGE, {
-      headers: {
+      form: {
-        'content-type': 'application/x-www-form-urlencoded'
-      },
-      data: {
         firstName: 'John',
         lastName: 'Doe',
         file: 'f.js',
@@ -784,10 +781,7 @@ it('should support multipart/form-data', async function({ context, page, server
   const [{ error, fields, files, serverRequest }, response] = await Promise.all([
     formReceived,
     context._request.post(server.EMPTY_PAGE, {
-      headers: {
+      multipart: {
-        'content-type': 'multipart/form-data'
-      },
-      data: {
         firstName: 'John',
         lastName: 'Doe',
         file
@@ -819,10 +813,7 @@ it('should support multipart/form-data with ReadSream values', async function({
   const [{ error, fields, files, serverRequest }, response] = await Promise.all([
     formReceived,
     context._request.post(server.EMPTY_PAGE, {
-      headers: {
+      multipart: {
-        'content-type': 'multipart/form-data'
-      },
-      data: {
         firstName: 'John',
         lastName: 'Doe',
         readStream
@@ -841,17 +832,24 @@ it('should support multipart/form-data with ReadSream values', async function({
   expect(response.status()).toBe(200);
 });
 
-it('should throw nice error on unsupported encoding', async function({ context, server }) {
+it('should serialize data to json regardless of content-type', async function({ context, server }) {
-  const error = await context._request.post(server.EMPTY_PAGE, {
+  const data = {
-    headers: {
+    firstName: 'John',
-      'content-type': 'unknown'
+    lastName: 'Doe',
-    },
+  };
-    data: {
+  const [req] = await Promise.all([
-      firstName: 'John',
+    server.waitForRequest('/empty.html'),
-      lastName: 'Doe',
+    context._request.post(server.EMPTY_PAGE, {
-    }
+      headers: {
-  }).catch(e => e);
+        'content-type': 'unknown'
-  expect(error.message).toContain('Cannot serialize data using content type: unknown');
+      },
+      data
+    }),
+  ]);
+  expect(req.method).toBe('POST');
+  expect(req.headers['content-type']).toBe('unknown');
+  const body = (await req.postBody).toString('utf8');
+  expect(body).toEqual(JSON.stringify(data));
 });
 
 it('should throw nice error on unsupported data type', async function({ context, server }) {
@@ -867,9 +865,6 @@ it('should throw nice error on unsupported data type', async function({ context,
 it('should throw when data passed for unsupported request', async function({ context, server }) {
   const error = await context._request.fetch(server.EMPTY_PAGE, {
     method: 'GET',
-    headers: {
-      'content-type': 'application/json'
-    },
     data: {
       foo: 'bar'
     }

types/types.d.ts

@@ -18,6 +18,7 @@ import { Protocol } from './protocol';
 import { ChildProcess } from 'child_process';
 import { EventEmitter } from 'events';
 import { Readable } from 'stream';
+import { ReadStream } from 'fs';
 import { Serializable, EvaluationArgument, PageFunction, PageFunctionOn, SmartHandle, ElementHandleForTag, BindingSource } from './structs';
 
 type PageWaitForSelectorOptionsNotHidden = PageWaitForSelectorOptions & {
@@ -12682,12 +12683,9 @@ export interface FetchRequest {
    */
   fetch(urlOrRequest: string|Request, options?: {
     /**
-     * Allows to set post data of the fetch. If the data parameter is an object, it will be serialized the following way:
+     * Allows to set post data of the request. If the data parameter is an object, it will be serialized to json string and
-     * - If `content-type` header is set to `application/x-www-form-urlencoded` the object will be serialized as html form
+     * `content-type` header will be set to `application/json` if not explicitly set. Otherwise the `content-type` header will
-     *   using `application/x-www-form-urlencoded` encoding.
+     * be set to `application/octet-stream` if not explicitly set.
-     * - If `content-type` header is set to `multipart/form-data` the object will be serialized as html form using
-     *   `multipart/form-data` encoding.
-     * - Otherwise the object will be serialized to json string and `content-type` header will be set to `application/json`.
      */
     data?: string|Buffer|Serializable;
 
@@ -12696,6 +12694,13 @@ export interface FetchRequest {
      */
     failOnStatusCode?: boolean;
 
+    /**
+     * Provides an object that will be serialized as html form using `application/x-www-form-urlencoded` encoding and sent as
+     * this request body. If this parameter is specified `content-type` header will be set to
+     * `application/x-www-form-urlencoded` unless explicitly provided.
+     */
+    form?: { [key: string]: string|number|boolean; };
+
     /**
      * Allows to set HTTP headers.
      */
@@ -12711,6 +12716,29 @@ export interface FetchRequest {
      */
     method?: string;
 
+    /**
+     * Provides an object that will be serialized as html form using `multipart/form-data` encoding and sent as this request
+     * body. If this parameter is specified `content-type` header will be set to `multipart/form-data` unless explicitly
+     * provided. File values can be passed either as [`fs.ReadStream`](https://nodejs.org/api/fs.html#fs_class_fs_readstream)
+     * or as file-like object containing file name, mime-type and its content.
+     */
+    multipart?: { [key: string]: string|number|boolean|ReadStream|{
+      /**
+       * File name
+       */
+      name: string;
+
+      /**
+       * File type
+       */
+      mimeType: string;
+
+      /**
+       * File content
+       */
+      buffer: Buffer;
+    }; };
+
     /**
      * Query parameters to be send with the URL.
      */
@@ -12763,12 +12791,9 @@ export interface FetchRequest {
    */
   post(urlOrRequest: string|Request, options?: {
     /**
-     * Allows to set post data of the fetch. If the data parameter is an object, it will be serialized the following way:
+     * Allows to set post data of the request. If the data parameter is an object, it will be serialized to json string and
-     * - If `content-type` header is set to `application/x-www-form-urlencoded` the object will be serialized as html form
+     * `content-type` header will be set to `application/json` if not explicitly set. Otherwise the `content-type` header will
-     *   using `application/x-www-form-urlencoded` encoding.
+     * be set to `application/octet-stream` if not explicitly set.
-     * - If `content-type` header is set to `multipart/form-data` the object will be serialized as html form using
-     *   `multipart/form-data` encoding.
-     * - Otherwise the object will be serialized to json string and `content-type` header will be set to `application/json`.
      */
     data?: string|Buffer|Serializable;
 
@@ -12777,6 +12802,13 @@ export interface FetchRequest {
      */
     failOnStatusCode?: boolean;
 
+    /**
+     * Provides an object that will be serialized as html form using `application/x-www-form-urlencoded` encoding and sent as
+     * this request body. If this parameter is specified `content-type` header will be set to
+     * `application/x-www-form-urlencoded` unless explicitly provided.
+     */
+    form?: { [key: string]: string|number|boolean; };
+
     /**
      * Allows to set HTTP headers.
      */
@@ -12787,6 +12819,29 @@ export interface FetchRequest {
      */
     ignoreHTTPSErrors?: boolean;
 
+    /**
+     * Provides an object that will be serialized as html form using `multipart/form-data` encoding and sent as this request
+     * body. If this parameter is specified `content-type` header will be set to `multipart/form-data` unless explicitly
+     * provided. File values can be passed either as [`fs.ReadStream`](https://nodejs.org/api/fs.html#fs_class_fs_readstream)
+     * or as file-like object containing file name, mime-type and its content.
+     */
+    multipart?: { [key: string]: string|number|boolean|ReadStream|{
+      /**
+       * File name
+       */
+      name: string;
+
+      /**
+       * File type
+       */
+      mimeType: string;
+
+      /**
+       * File content
+       */
+      buffer: Buffer;
+    }; };
+
     /**
      * Query parameters to be send with the URL.
      */

utils/generate_types/overrides.d.ts

@@ -17,6 +17,7 @@ import { Protocol } from './protocol';
 import { ChildProcess } from 'child_process';
 import { EventEmitter } from 'events';
 import { Readable } from 'stream';
+import { ReadStream } from 'fs';
 import { Serializable, EvaluationArgument, PageFunction, PageFunctionOn, SmartHandle, ElementHandleForTag, BindingSource } from './structs';
 
 type PageWaitForSelectorOptionsNotHidden = PageWaitForSelectorOptions & {