Added support for spec-compliant FormData & Blob types;

.eslintrc.cjs

@@ -1,12 +1,12 @@
 module.exports = {
   "env": {
     "browser": true,
-    "es2017": true,
+    "es2018": true,
     "node": true
   },
   "extends": "eslint:recommended",
   "parserOptions": {
-    "ecmaVersion": 2017,
+    "ecmaVersion": 2018,
     "sourceType": "module"
   },
   "rules": {

lib/adapters/http.js

@@ -19,6 +19,8 @@ import stream from 'stream';
 import AxiosHeaders from '../core/AxiosHeaders.js';
 import AxiosTransformStream from '../helpers/AxiosTransformStream.js';
 import EventEmitter from 'events';
+import formDataToStream from "../helpers/formDataToStream.js";
+import readBlob from "../helpers/readBlob.js";
 import ZlibHeaderTransformStream from '../helpers/ZlibHeaderTransformStream.js';
 
 const zlibOptions = {
@@ -243,9 +245,27 @@ export default isHttpAdapterSupported && function httpAdapter(config) {
     let maxUploadRate = undefined;
     let maxDownloadRate = undefined;
 
-    // support for https://www.npmjs.com/package/form-data api
-    if (utils.isFormData(data) && utils.isFunction(data.getHeaders)) {
+    // support for spec compliant FormData objects
+    if (utils.isSpecCompliantForm(data)) {
+      const userBoundary = headers.getContentType(/boundary=([-_\w\d]{10,70})/i);
+
+      data = formDataToStream(data, (formHeaders) => {
+        headers.set(formHeaders);
+      }, {
+        tag: `axios-${VERSION}-boundary`,
+        boundary: userBoundary && userBoundary[1] || undefined
+      });
+      // support for https://www.npmjs.com/package/form-data api
+    } else if (utils.isFormData(data) && utils.isFunction(data.getHeaders)) {
       headers.set(data.getHeaders());
+      if (utils.isFunction(data.getLengthSync)) { // check if the undocumented API exists
+        const knownLength = data.getLengthSync();
+        !utils.isUndefined(knownLength) && headers.setContentLength(knownLength, false);
+      }
+    } else if (utils.isBlob(data)) {
+      data.size && headers.setContentType(data.type || 'application/octet-stream');
+      headers.setContentLength(data.size || 0);
+      data = stream.Readable.from(readBlob(data));
     } else if (data && !utils.isStream(data)) {
       if (Buffer.isBuffer(data)) {
         // Nothing to do...
@@ -262,7 +282,7 @@ export default isHttpAdapterSupported && function httpAdapter(config) {
       }
 
       // Add Content-Length header if data exists
-      headers.set('Content-Length', data.length, false);
+      headers.setContentLength(data.length, false);
 
       if (config.maxBodyLength > -1 && data.length > config.maxBodyLength) {
         return reject(new AxiosError(

lib/env/classes/FormData.js

@@ -1,2 +1,2 @@
-import FormData from 'form-data';
-export default FormData;
+import _FormData from 'form-data';
+export default typeof FormData !== 'undefined' ? FormData : _FormData;

lib/helpers/formDataToStream.js

@@ -0,0 +1,110 @@
+import {Readable} from 'stream';
+import utils from "../utils.js";
+import readBlob from "./readBlob.js";
+
+const BOUNDARY_ALPHABET = utils.ALPHABET.ALPHA_DIGIT + '-_';
+
+const textEncoder = new TextEncoder();
+
+const CRLF = '\r\n';
+const CRLF_BYTES = textEncoder.encode(CRLF);
+const CRLF_BYTES_COUNT = 2;
+
+class FormDataPart {
+  constructor(name, value) {
+    const {escapeName} = this.constructor;
+    const isStringValue = utils.isString(value);
+
+    let headers = `Content-Disposition: form-data; name="${escapeName(name)}"${
+      !isStringValue && value.name ? `; filename="${escapeName(value.name)}"` : ''
+    }${CRLF}`;
+
+    if (isStringValue) {
+      value = textEncoder.encode(String(value).replace(/\r?\n|\r\n?/g, CRLF));
+    } else {
+      headers += `Content-Type: ${value.type || "application/octet-stream"}${CRLF}`
+    }
+
+    this.headers = textEncoder.encode(headers + CRLF);
+
+    this.contentLength = isStringValue ? value.byteLength : value.size;
+
+    this.size = this.headers.byteLength + this.contentLength + CRLF_BYTES_COUNT;
+
+    this.name = name;
+    this.value = value;
+  }
+
+  async *encode(){
+    yield this.headers;
+
+    const {value} = this;
+
+    if(utils.isTypedArray(value)) {
+      yield value;
+    } else {
+      yield* readBlob(value);
+    }
+
+    yield CRLF_BYTES;
+  }
+
+  static escapeName(name) {
+      return String(name).replace(/[\r\n"]/g, (match) => ({
+        '\r' : '%0D',
+        '\n' : '%0A',
+        '"' : '%22',
+      }[match]));
+  }
+}
+
+const formDataToStream = (form, headersHandler, options) => {
+  const {
+    tag = 'form-data-boundary',
+    size = 25,
+    boundary = tag + '-' + utils.generateString(size, BOUNDARY_ALPHABET)
+  } = options || {};
+
+  if(!utils.isFormData(form)) {
+    throw TypeError('FormData instance required');
+  }
+
+  if (boundary.length < 1 || boundary.length > 70) {
+    throw Error('boundary must be 10-70 characters long')
+  }
+
+  const boundaryBytes = textEncoder.encode('--' + boundary + CRLF);
+  const footerBytes = textEncoder.encode('--' + boundary + '--' + CRLF + CRLF);
+  let contentLength = footerBytes.byteLength;
+
+  const parts = Array.from(form.entries()).map(([name, value]) => {
+    const part = new FormDataPart(name, value);
+    contentLength += part.size;
+    return part;
+  });
+
+  contentLength += boundaryBytes.byteLength * parts.length;
+
+  contentLength = utils.toFiniteNumber(contentLength);
+
+  const computedHeaders = {
+    'Content-Type': `multipart/form-data; boundary=${boundary}`
+  }
+
+  if (Number.isFinite(contentLength)) {
+    computedHeaders['Content-Length'] = contentLength;
+  }
+
+  headersHandler && headersHandler(computedHeaders);
+
+  return Readable.from((async function *() {
+    for(const part of parts) {
+      yield boundaryBytes;
+      yield* part.encode();
+    }
+
+    yield footerBytes;
+  })());
+};
+
+export default formDataToStream;

lib/helpers/readBlob.js

@@ -0,0 +1,15 @@
+const {asyncIterator} = Symbol;
+
+const readBlob = async function* (blob) {
+  if (blob.stream) {
+    yield* blob.stream()
+  } else if (blob.arrayBuffer) {
+    yield await blob.arrayBuffer()
+  } else if (blob[asyncIterator]) {
+    yield* asyncIterator.call(blob);
+  } else {
+    yield blob;
+  }
+}
+
+export default readBlob;

lib/helpers/toFormData.js

@@ -2,7 +2,8 @@
 
 import utils from '../utils.js';
 import AxiosError from '../core/AxiosError.js';
-import envFormData from '../env/classes/FormData.js';
+// temporary hotfix to avoid circular references until AxiosURLSearchParams is refactored
+import PlatformFormData from '../platform/node/classes/FormData.js';
 
 /**
  * Determines if the given thing is a array or js object.
@@ -59,17 +60,6 @@ const predicates = utils.toFlatObject(utils, {}, null, function filter(prop) {
   return /^is[A-Z]/.test(prop);
 });
 
-/**
- * If the thing is a FormData object, return true, otherwise return false.
- *
- * @param {unknown} thing - The thing to check.
- *
- * @returns {boolean}
- */
-function isSpecCompliant(thing) {
-  return thing && utils.isFunction(thing.append) && thing[Symbol.toStringTag] === 'FormData' && thing[Symbol.iterator];
-}
-
 /**
  * Convert a data object to FormData
  *
@@ -99,7 +89,7 @@ function toFormData(obj, formData, options) {
   }
 
   // eslint-disable-next-line no-param-reassign
-  formData = formData || new (envFormData || FormData)();
+  formData = formData || new (PlatformFormData || FormData)();
 
   // eslint-disable-next-line no-param-reassign
   options = utils.toFlatObject(options, {
@@ -117,7 +107,7 @@ function toFormData(obj, formData, options) {
   const dots = options.dots;
   const indexes = options.indexes;
   const _Blob = options.Blob || typeof Blob !== 'undefined' && Blob;
-  const useBlob = _Blob && isSpecCompliant(formData);
+  const useBlob = _Blob && utils.isSpecCompliantForm(formData);
 
   if (!utils.isFunction(visitor)) {
     throw new TypeError('visitor must be a function');

lib/utils.js

@@ -512,7 +512,7 @@ const matchAll = (regExp, str) => {
 const isHTMLForm = kindOfTest('HTMLFormElement');
 
 const toCamelCase = str => {
-  return str.toLowerCase().replace(/[_-\s]([a-z\d])(\w*)/g,
+  return str.toLowerCase().replace(/[-_\s]([a-z\d])(\w*)/g,
     function replacer(m, p1, p2) {
       return p1.toUpperCase() + p2;
     }
@@ -596,6 +596,37 @@ const toFiniteNumber = (value, defaultValue) => {
   return Number.isFinite(value) ? value : defaultValue;
 }
 
+const ALPHA = 'abcdefghijklmnopqrstuvwxyz'
+
+const DIGIT = '0123456789';
+
+const ALPHABET = {
+  DIGIT,
+  ALPHA,
+  ALPHA_DIGIT: ALPHA + ALPHA.toUpperCase() + DIGIT
+}
+
+const generateString = (size = 16, alphabet = ALPHABET.ALPHA_DIGIT) => {
+  let str = '';
+  const {length} = alphabet;
+  while (size--) {
+    str += alphabet[Math.random() * length|0]
+  }
+
+  return str;
+}
+
+/**
+ * If the thing is a FormData object, return true, otherwise return false.
+ *
+ * @param {unknown} thing - The thing to check.
+ *
+ * @returns {boolean}
+ */
+function isSpecCompliantForm(thing) {
+  return !!(thing && isFunction(thing.append) && thing[Symbol.toStringTag] === 'FormData' && thing[Symbol.iterator]);
+}
+
 const toJSONObject = (obj) => {
   const stack = new Array(10);
 
@@ -673,5 +704,8 @@ export default {
   findKey,
   global: _global,
   isContextDefined,
+  ALPHABET,
+  generateString,
+  isSpecCompliantForm,
   toJSONObject
 };

package.json

@@ -89,6 +89,7 @@
     "es6-promise": "^4.2.8",
     "eslint": "^8.17.0",
     "express": "^4.18.1",
+    "formdata-node": "^5.0.0",
     "formidable": "^2.0.1",
     "fs-extra": "^10.1.0",
     "get-stream": "^3.0.0",
@@ -126,7 +127,8 @@
   },
   "browser": {
     "./lib/adapters/http.js": "./lib/helpers/null.js",
-    "./lib/platform/node/index.js": "./lib/platform/browser/index.js"
+    "./lib/platform/node/index.js": "./lib/platform/browser/index.js",
+    "./lib/platform/node/classes/FormData.js": "./lib/helpers/null.js"
   },
   "jsdelivr": "dist/axios.min.js",
   "unpkg": "dist/axios.min.js",
@@ -201,4 +203,4 @@
       "@commitlint/config-conventional"
     ]
   }
-}
+}