使用BlobstoreUploadHandler處理圖片上傳並返回JSON消息

Question

我試圖上傳一個圖片到create_upload_url（）創建的URL，使用默認的BlobstoreUploadHandler處理它，然後用get_serving_url（）函數返回一個JSON消息給客戶端。圖像的URL。我的代碼如下：

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) 

問題是在客戶端沒有收到響應。 AppEngine日誌在請求中顯示狀態200。當使用閃光燈進行請求時，狀態碼是200，並且沒有響應主體，但是使用HTML5將輸出狀態「（取消）」。我不知道發生了什麼事。從我在互聯網上看到的所有代碼片段都可以發揮作用。請幫忙！謝謝。

Answer 1

事實證明，這是一個HTML5跨來源資源共享的問題。您可以通過在響應中添加正確的標頭來解決此問題：

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)) 

Answer 2

要處理上傳並返回JSON響應，您需要將upload_handler重定向到將返回JSON響應的處理程序。

下面是一個例子：

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))