Python请求将图像文件发布到rails回形针，rails:params ParseE

Question

我正在用googledriveapi下载一个图像，并用回形针将文件上传到我的railsapi。你知道吗

我下载了Google驱动器映像为BytesIO()，并使用Pillow将字节保存/转换为一个名为tmp.png的映像。我现在使用请求将文件发布到Rails：

# I have a io.BytesIO() instance fh, with the image byte data.

fh.seek(0)
img = Image.open(fh)
img.save('tmp.png')
response = requests.post(LOCALHOST_MEDIA_ENDPOINT,
                         data={
                             "media": {
                                 "attachment": open('tmp.png', 'rb') 
                                 # I've also tried just using img
                             }
                         },
                         headers={
                             'content-type': 'application/json'
                         })

媒体/回形针控制器可以工作；它已经在一个带有文件dropzone的节点应用程序上通过formsubmit进行了测试。但是，当我发出此请求时，我的localhost日志会显示：

Started POST "/media" for 172.18.0.1 at 2017-11-14 02:16:35 +0000
web_1  | Error occurred while parsing request parameters.
web_1  | Contents:
web_1  | 
web_1  | media=attachment
web_1  |   
web_1  | ActionDispatch::Http::Parameters::ParseError (822: unexpected token at 'media=attachment'):
web_1  |   
web_1  | actionpack (5.1.2) lib/action_dispatch/http/parameters.rb:113:in `rescue in parse_formatted_parameters'
web_1  | actionpack (5.1.2) lib/action_dispatch/http/parameters.rb:107:in `parse_formatted_parameters'
web_1  | actionpack (5.1.2) lib/action_dispatch/http/request.rb:358:in `block in POST'
web_1  | rack (2.0.3) lib/rack/request.rb:57:in `fetch'
web_1  | rack (2.0.3) lib/rack/request.rb:57:in `fetch_header'
web_1  | actionpack (5.1.2) lib/action_dispatch/http/request.rb:357:in `POST'
web_1  | actionpack (5.1.2) lib/action_controller/metal/params_wrapper.rb:286:in `_wrapper_enabled?'
web_1  | actionpack (5.1.2) lib/action_controller/metal/params_wrapper.rb:235:in `process_action'
web_1  | activerecord (5.1.2) lib/active_record/railties/controller_runtime.rb:22:in `process_action'
web_1  | actionpack (5.1.2) lib/abstract_controller/base.rb:124:in `process'
web_1  | actionpack (5.1.2) lib/action_controller/metal.rb:189:in `dispatch'
web_1  | actionpack (5.1.2) lib/action_controller/metal.rb:253:in `dispatch'
web_1  | actionpack (5.1.2) lib/action_dispatch/routing/route_set.rb:49:in `dispatch'
web_1  | actionpack (5.1.2) lib/action_dispatch/routing/route_set.rb:31:in `serve'
web_1  | actionpack (5.1.2) lib/action_dispatch/journey/router.rb:46:in `block in serve'
web_1  | actionpack (5.1.2) lib/action_dispatch/journey/router.rb:33:in `each'
web_1  | actionpack (5.1.2) lib/action_dispatch/journey/router.rb:33:in `serve'
web_1  | actionpack (5.1.2) lib/action_dispatch/routing/route_set.rb:832:in `call'
web_1  | omniauth (1.6.1) lib/omniauth/strategy.rb:189:in `call!'
web_1  | omniauth (1.6.1) lib/omniauth/strategy.rb:167:in `call'
web_1  | omniauth (1.6.1) lib/omniauth/builder.rb:63:in `call'
web_1  | rack (2.0.3) lib/rack/session/abstract/id.rb:232:in `context'
web_1  | rack (2.0.3) lib/rack/session/abstract/id.rb:226:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/cookies.rb:613:in `call'
web_1  | olive_branch (1.2.3) lib/olive_branch/middleware.rb:14:in `call'
web_1  | warden (1.2.7) lib/warden/manager.rb:36:in `block in call'
web_1  | warden (1.2.7) lib/warden/manager.rb:35:in `catch'
web_1  | warden (1.2.7) lib/warden/manager.rb:35:in `call'
web_1  | rack (2.0.3) lib/rack/etag.rb:25:in `call'
web_1  | rack (2.0.3) lib/rack/conditional_get.rb:38:in `call'
web_1  | rack (2.0.3) lib/rack/head.rb:12:in `call'
web_1  | activerecord (5.1.2) lib/active_record/migration.rb:556:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/callbacks.rb:26:in `block in call'
web_1  | activesupport (5.1.2) lib/active_support/callbacks.rb:97:in `run_callbacks'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/callbacks.rb:24:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/executor.rb:12:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/debug_exceptions.rb:59:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/show_exceptions.rb:31:in `call'
web_1  | railties (5.1.2) lib/rails/rack/logger.rb:36:in `call_app'
web_1  | railties (5.1.2) lib/rails/rack/logger.rb:24:in `block in call'
web_1  | activesupport (5.1.2) lib/active_support/tagged_logging.rb:69:in `block in tagged'
web_1  | activesupport (5.1.2) lib/active_support/tagged_logging.rb:26:in `tagged'
web_1  | activesupport (5.1.2) lib/active_support/tagged_logging.rb:69:in `tagged'
web_1  | railties (5.1.2) lib/rails/rack/logger.rb:24:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/remote_ip.rb:79:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/request_id.rb:25:in `call'
web_1  | rack (2.0.3) lib/rack/runtime.rb:22:in `call'
web_1  | activesupport (5.1.2) lib/active_support/cache/strategy/local_cache_middleware.rb:27:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/executor.rb:12:in `call'
web_1  | actionpack (5.1.2) lib/action_dispatch/middleware/static.rb:125:in `call'
web_1  | rack (2.0.3) lib/rack/sendfile.rb:111:in `call'
web_1  | rack-cors (1.0.1) lib/rack/cors.rb:93:in `call'
web_1  | railties (5.1.2) lib/rails/engine.rb:522:in `call'
web_1  | puma (3.9.1) lib/puma/configuration.rb:224:in `call'
web_1  | puma (3.9.1) lib/puma/server.rb:602:in `handle_request'
web_1  | puma (3.9.1) lib/puma/server.rb:435:in `process_client'
web_1  | puma (3.9.1) lib/puma/server.rb:299:in `block in run'
web_1  | puma (3.9.1) lib/puma/thread_pool.rb:120:in `block in spawn_thread'

我的控制器：

def create
  @medium = Medium.new(medium_params)

  if @medium.save
    render json: @medium.to_json(
             :only => [:id, :title, :caption],
             :methods => [
               :attachment_url,
               :medium_attachment_url,
               :thumb_attachment_url
             ]
           ), status: :created, location: @medium
  else
    render json: @medium.errors, status: :unprocessable_entity
  end
end
...
def medium_params
  params.require(:medium).permit(
     # other irrelevant string/int permitted params
    :attachment
  )
end

我在想，也许这个请求中的图像编码方式与表单提交数据的方式不同。但不幸的是，我被困住了。你知道吗

Answer 1

创建一个多部分/表单数据请求，而不是application/json。你知道吗

或者，如果您想使用base64编码的文件内容，您必须做一些额外的工作来解码图像并将其分配给papercip（Use paperclip for saving base64 images obtained from an api）