java - 使用谷歌应用引擎将文件上传到 blobstore 时出现 http 400 错误

Question

我正在尝试使用 google app engine blobstore 上传文件。

它应该像这样工作:您调用 BlobstoreService 来获取上传 URL，并提供回调 URL。客户端被重定向到上传 URL，发送数据，然后当他们完成后，他们将被重定向到回调 URL，其中包含几个代表 blobstore key 的参数。

正如我们将看到的，开发服务器的行为与生产服务器不同。

在生产环境中，我的代码完成了上传，然后没有重定向回我的回调 URL，而是收到了 400 错误响应(暗示我的请求有问题)。我如何在生产中调试它？我不知道如何打开 blobstore 的日志记录。

所以我尝试在开发服务器上本地运行它。这一次，如果我不设置“内容长度”属性，我会收到 411(未设置内容长度)。但如果我尝试设置该属性，我会得到“IllegalStateException:已经连接”。这些异常都不会发生在生产环境中。

所以我不知道下一步该去哪里。我需要让它在 dev 上工作，希望我可以在本地调试 blobstore，或者弄清楚为什么它不能在生产中的 blobstore 上工作。

    public void upload(String uri, File file) throws IOException    {
    HttpURLConnection conn=null;
    HttpURLConnection conn2=null;
    FileInputStream fileInputStream = null;
    DataOutputStream dos=null;
    try {
        String lineEnd = "\r\n";
        String twoHyphens = "--";
        String boundary = "*****";
        int bytesRead, bytesAvailable, bufferSize;
        byte[] buffer;
        int maxBufferSize = 1 * 1024 * 1024; 
        // open a URL connection to the Servlet
        fileInputStream = new FileInputStream(file);
        URL url = new URL(uri);

        // Open a HTTP  connection to  the URL
        conn = (HttpURLConnection) url.openConnection();
        conn.setDoInput(true); // Allow Inputs
        conn.setDoOutput(true); // Allow Outputs
        conn.setUseCaches(false); // Don't use a Cached Copy
        conn.setInstanceFollowRedirects(false);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("ENCTYPE", "multipart/form-data");
        conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
//          conn.setChunkedStreamingMode(1024);
        conn.setRequestProperty("content-length", String.valueOf(file.length()));   //caused IllegalStateException "Already connected" locally, but not remotely

        log("Orignal URL: " + conn.getURL());
        //conn.connect();   //TODO duplicates url.openConnection() above?
        conn.getInputStream();  //so we can follow the redirect
        String redirectedUrl = conn.getHeaderField("Location");
        log("Redirected URL: " + redirectedUrl);
        //this is horrible and messy but let's get it working then clean it up later

        conn.disconnect();
        url = new URL(redirectedUrl);

        // Open a new HTTP  connection to  the URL
        conn2 = (HttpURLConnection) url.openConnection();
        conn2.setDoInput(true); // Allow Inputs
        conn2.setDoOutput(true); // Allow Outputs
        conn2.setUseCaches(false); // Don't use a Cached Copy
        conn2.setInstanceFollowRedirects(false);
        conn2.setRequestMethod("POST");
        conn2.setRequestProperty("Connection", "Keep-Alive");
        conn2.setRequestProperty("ENCTYPE", "multipart/form-data");
        conn2.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
        conn2.setChunkedStreamingMode(maxBufferSize);
        conn2.setRequestProperty("Content-Length", String.valueOf(file.length()));
        conn2.connect();
        dos = new DataOutputStream(conn2.getOutputStream());

        dos.writeBytes(twoHyphens + boundary + lineEnd);
        dos.writeBytes("Content-Disposition: form-data; name=\"myFile\";filename=\""+file.getName()+"\"" + lineEnd);
        dos.writeBytes(lineEnd);

        // create a buffer of  maximum size
        bytesAvailable = fileInputStream.available();

        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        buffer = new byte[bufferSize];

        // read file and write it into form...
        bytesRead = fileInputStream.read(buffer, 0, bufferSize); 

        while (bytesRead > 0) {
            dos.write(buffer, 0, bufferSize);
            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);  
        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);
        dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

        // Responses from the server (code and message)
        int serverResponseCode = conn2.getResponseCode();
        String serverResponseMessage = conn2.getResponseMessage();
        //we are expecting another redirect here
        log("aaaargh! 400 instead of 302! "+serverResponseCode+" to "+conn2.getHeaderField("Location"));
    }catch (IOException e)  {
        log(e.getMessage());
        throw e;
    }catch(Exception e) {
        log(e.getMessage());
        throw new IOException(e);
    }   finally {
        //close the streams //
        if (dos!=null)  {   
            try {
                dos.flush();
                dos.close();
            }catch(IOException ioe){}
        }
        if (fileInputStream!=null)
            try {
                fileInputStream.close();
            }catch(IOException ioe){}

        if (conn!=null )
            try {
                conn.disconnect();
            }catch(Exception ioe){}

        if (conn2!=null)
            try {
                conn2.disconnect();
            }catch(Exception ioe){}

    }
}

注意上面的 serverResponseMessage 字符串作为“错误请求”从生产 blobstore 返回

Answer 1

我不知道如何从 Android 客户端执行此操作，但我可以向您展示我们如何从 javascript 客户端执行此操作，因为它可能会给您一些指示。

客户端非常简单(这是一个 angular.js Controller )，我们获取要使用的 url 并上传到它

// model file upload
    $scope.onFileSelect = function ($files) {
        $scope.uploadStatus = 'loading';
        for (var i = 0; i < $files.length; i++) {
            var file = $files[i];
            console.log(file);

            $http.get('/endpoints/prototype/' + $scope.prototype.key + '/file/url')
                .success((function (data) {
                        console.log(data);

                        $scope.upload = $upload.upload({
                            url: data,
                            withCredentials: true,
                            file: file
                        })
                        .success(function (data) {
                            console.log(data);
                            $scope.prototype.modelFile = data;
                        })
                        .error(function (data, status) {
                            console.error(data);
                            $scope.uploadStatus = 'error';
                            $scope.uploadError = status;
                        });
                }))
                .error((function (data, status) {
                    console.error(data);
                    $scope.uploadStatus = 'error';
                    $scope.uploadError = status;
                }));
        }
    };

服务器端，我们有一个端点，它返回用于发布的 URL(这是一个 Spring MVC Controller )。注意我们在createUploadUrl()中指定成功路径

@RequestMapping(value = "/endpoints/prototype/{key}/file/url", method = RequestMethod.GET)
@ResponseBody
public String getFileUploadUrl(@PathVariable("key") String prototypeKey) {
    final UploadOptions uploadOptions = Builder.withDefaults()
          .googleStorageBucketName("palmyra-prototype-store");

    return blobstoreService.createUploadUrl("/endpoints/prototype/" + prototypeKey + "/file", uploadOptions);
}

最后是上传成功后调用的端点

@RequestMapping(value = "/endpoints/prototype/{key}/file", method = RequestMethod.POST)
@ResponseBody
public String handleFileUpload(@PathVariable("key") String prototypeKey, HttpServletRequest request) {
    final Map<String, List<BlobKey>> blobs = blobstoreService.getUploads(request);
    final Map<String, List<FileInfo>> allFileInfos = blobstoreService.getFileInfos(request);

    final List<BlobKey> blobKeys = blobs.get(INPUT_FILE_NAME);
    final List<FileInfo> fileInfos = allFileInfos.get(INPUT_FILE_NAME);

    if ((blobKeys == null) || (fileInfos == null)) {
        return "You failed to upload a model file for " + prototypeKey + " because the file was empty.";
    } else if ((blobKeys.size() == 1) && (fileInfos.size() == 1)) {
        final BlobKey blobKey = blobKeys.get(0);
        final FileInfo fileInfo = fileInfos.get(0);

        final Prototype prototype = prototypeService.findByKey(prototypeKey);
        prototype.setModelFile(blobInfoFactory.loadBlobInfo(blobKey).getFilename());
        prototype.setUploadedModelFile(fileInfo.getGsObjectName());

        prototypeService.updatePrototype(prototypeKey, prototype);

        return blobInfoFactory.loadBlobInfo(blobKey).getFilename();
    } else {
        return "One and only one file is allowed to be uploaded. The related prototype is " + prototypeKey +
              ". The number of blobs is " + blobKeys.size() + ", the number of files is " + fileInfos.size();
    }
}

就是这样，希望它能帮助你解决你的问题。