Question

我有一个迷你应用，我必须从浏览器将表单数据发布到端点。

这是我的帖子：

var formData = new FormData();
formData.append('blobImage', blob, 'imagem' + (new Date()).getTime());

return $http({
  method: 'POST',
  url: api + '/url',
  data: formData,
  headers: {'Content-Type': 'multipart/form-data'}
})

边界似乎是由formData添加到参数中，但是，我不能让它在标题中发送，我该怎么做？

Answer 1

好吧，似乎标题ContentType应该是未定义的，以便添加正确的边界

Answer 2

正确的方法是不设置Content-Type标头。

示例：

import { http } from '@angular/common/http'

function sendPostData(form: FormData) {
  const url = `https://post-url-example.com/submit`;
  const options = {
    headers: new HttpHeaders({
      Authorization: `Bearer auth-token`
    })
  };

  return http.post(url, form, options);
}

进一步添加Pablo's answer。

当HTTP请求正文为FormData类型时，angular将Content-Type头分配给浏览器。 detectContentTypeHeader()将在null请求主体上返回FormData，并且不会设置请求标头。

这是在@angular/commons/http/src/xhr.ts模块上。

  // Auto-detect the Content-Type header if one isn't present already.
  if (!req.headers.has('Content-Type')) {
    const detectedType = req.detectContentTypeHeader();
    // Sometimes Content-Type detection fails.
    if (detectedType !== null) {
      xhr.setRequestHeader('Content-Type', detectedType);
    }
  }

基于请求正文的内容类型检测：

  detectContentTypeHeader(): string|null {
    // An empty body has no content type.
    if (this.body === null) {
      return null;
    }
    // FormData bodies rely on the browser's content type assignment.
    if (isFormData(this.body)) {
      return null;
    }
    // Blobs usually have their own content type. If it doesn't, then
    // no type can be inferred.
    if (isBlob(this.body)) {
      return this.body.type || null;
    }
    // Array buffers have unknown contents and thus no type can be inferred.
    if (isArrayBuffer(this.body)) {
      return null;
    }
    // Technically, strings could be a form of JSON data, but it's safe enough
    // to assume they're plain strings.
    if (typeof this.body === 'string') {
      return 'text/plain';
    }
    // `HttpUrlEncodedParams` has its own content-type.
    if (this.body instanceof HttpParams) {
      return 'application/x-www-form-urlencoded;charset=UTF-8';
    }
    // Arrays, objects, and numbers will be encoded as JSON.
    if (typeof this.body === 'object' || typeof this.body === 'number' ||
        Array.isArray(this.body)) {
      return 'application/json';
    }
    // No type could be inferred.
    return null;
  }

来源：

FormData如何在multipart / form-data中获取或设置边界 - Angular

2 个答案: