[英]How to parse multipart/form-data?
我有一个用Go
编写的服务器。
基本上,它接收POST请求并作为multipart / form-data发送一些文件作为响应。
以下是服务器代码:
func ColorTransferHandler(w http.ResponseWriter, r *http.Request) {
... some routine...
w.WriteHeader(http.StatusOK)
mw := multipart.NewWriter(w)
filename := "image_to_send_back.png"
part, err := mw.CreateFormFile("image", filename)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
local_file, err := os.Open(filename)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
local_file_content, err := ioutil.ReadAll(local_file)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
part.Write(local_file_content)
w.Header().Set("Content-Type", mw.FormDataContentType())
if err := mw.Close(); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
}
适用于Android的Java
客户端代码:
public class ConnectionUtility {
private final String boundary;
private static final String LINE_FEED = "\r\n";
private HttpURLConnection httpConn;
private String charset;
private OutputStream outputStream;
private PrintWriter writer;
public List<String> finish() throws IOException {
// ...
// content filling
// ...
writer.append(LINE_FEED).flush();
writer.append("--" + boundary + "--").append(LINE_FEED);
writer.close();
List<String> response = new ArrayList<String>();
// checks server's status code first
int status = httpConn.getResponseCode();
if (status == HttpURLConnection.HTTP_OK) {
BufferedReader reader = new BufferedReader(new InputStreamReader(httpConn.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
response.add(line);
}
reader.close();
httpConn.disconnect();
} else {
throw new IOException("Server returned non-OK status: " + status);
}
return response;
}
以下是我的问题:
1.如何编辑此功能以获取该图像文件并将其保存在驱动器上?
2.也许我可以使用一些库来做到这一点?
帮助将不胜感激
首先,我建议您使用包装器库来管理网络连接,因为需要一些经验才能以正确的方式处理它们。 我不建议您使用HttpURLConnection
手动制作multipart
请求
安卓系统
如果您不想手动配置连接,则可以尝试使用OkHTTP或什至Retrofit 。
好的HTTP
这是一个基本示例,我省略了某些部分,例如异常处理。 另外请注意,您不需要为每个呼叫都创建客户端。
OkHttpClient client = new OkHttpClient.Builder().build();
RequestBody body = new MultipartBody.Builder().setType(MultipartBody.FORM)
.addFormDataPart("image_file", imageFileName, RequestBody.create(
MediaType.parse("image/jpeg"), new File(pathToImage)));
.addFormDataPart("anyOtherFormArg", arg1)
.addFormDataPart("anotherArg", arg2)
.build();
Request request = new Request.Builder().url(url).post(body).build();
Response response = client.newCall(request).execute();
result = response.body().string();
翻新
改造仅通过一个漂亮的界面来包装基础网络请求
@Multipart
@POST("endpoint/image")
Observable<ResponseBody> uploadImage(@Part("arg1") RequestBody arg1,
@Part MultipartBody.Part image);
去服务器
在服务器端,您可以尝试使用
func uploadHandler(w http.ResponseWriter, r *http.Request) {
if r.Method == "POST" {
err := r.ParseMultipartForm(32 << 20) // 32MB max upload size
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
m := r.MultipartForm
var file_name string
file, handler, err := r.FormFile("image_file")//get file
defer file.Close() //close the file when we finish
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
f, err := os.OpenFile("/path_to_save_image/"+handler.Filename, os.O_WRONLY|os.O_CREATE, 0666)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
file_name = handler.Filename
defer f.Close()
io.Copy(f, file)
//return something
w.Header().Set("Content-Type", "application/json")
w.Write("success")
w.WriteHeader(200)
}
w.Header().Set("Content-Type", "application/json")
w.Write("error")
w.WriteHeader(400)
}
这只是一个基本示例,请尝试理解每个部分并根据需要对其进行调整。
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