Question

我正在尝试将图像上传到使用create_upload_url（）创建的URL，使用默认的BlobstoreUploadHandler处理它，并使用图像的get_serving_url（）URL将JSON消息返回给客户端。我的代码如下：

class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):
    def post(self):
        response = {}

        upload_files = self.get_uploads('file')
        blob_info = upload_files[0]

        response['error'] = False
        response['message'] = "Image uploaded."
        response['image_url'] = images.get_serving_url(blob_info.key())

        self.response.headers['Content-Type'] = 'application/json'
        self.response.out.write(json.dumps(response))

app = webapp2.WSGIApplication(
    [('/_ih/upload_handler/', UploadHandler),
    ], debug=True)

问题是客户端没有收到任何响应。 AppEngine日志在请求中显示状态200。当使用flash进行请求时，状态代码为200且没有响应正文，但是使用HTML5将输出状态“（已取消）”。我不知道发生了什么事。从我在互联网上看到的所有代码片段，这应该工作。请帮忙！谢谢。

Answer 1

要处理上传并返回JSON响应，您需要从upload_handler重定向到将返回JSON响应的处理程序。

以下是一个例子：

class FileUploadHandler(blobstore_handlers.BlobstoreUploadHandler):

    def post(self):
        blob_info = self.get_uploads()[0]       
        self.redirect(self.uri_for("successfulUpload",blob_key = blob_info.key()))


class SuccessfulUpload(BaseHandler):

    def get(self, blob_Key):
        response['error'] = False
        response['message'] = "Image uploaded."
        response['image_url'] = images.get_serving_url(blobstore.BlobKey(blob_Key))
        self.response.headers['Content-Type'] = 'application/json'
        self.response.out.write(json.dumps(response))

Answer 2

事实证明，这是一个HTML5跨源资源共享问题。您可以通过在响应中添加正确的标头来解决此问题：

class UploadHandler(blobstore_handlers.BlobstoreUploadHandler):
    def post(self):
        response = {}

        upload_files = self.get_uploads('file')
        blob_info = upload_files[0]

        response['error'] = False
        response['message'] = "Image uploaded."
        response['image_url'] = images.get_serving_url(blob_info.key())


        self.response.headers.add_header("Access-Control-Allow-Methods", "POST") 
        self.response.headers.add_header("Access-Control-Allow-Origin", "*")

        self.response.headers['Content-Type'] = 'application/json'

        self.response.out.write(json.dumps(response))

使用BlobstoreUploadHandler处理图像上载并返回JSON消息

2 个答案: