直接上传文件至Google Cloud Document AI时遇400错误求助

问题排查与修复步骤 #

1. 修复表单验证调用错误 #

代码中if form.is_valid:缺少括号，导致表单验证逻辑未执行，可能跳过文件上传合法性检查，引发文件内容读取异常。修改为：

if form.is_valid():  # 补充括号，执行表单验证

2. 避免变量名冲突 #

创建Document AI请求时，request变量覆盖了原Django请求对象，虽当前代码未触发问题，但属于不良编码习惯，建议重命名：

# 重命名为docai_request，避免覆盖原request对象
docai_request = documentai.ProcessRequest(
    name=name,
    raw_document=documentai.RawDocument(content=image_content, mime_type="image/jpeg"),
)

result = docai_client.process_document(request=docai_request)

3. 确保文件内容正确读取且MIME类型匹配 #

• 添加验证代码确认文件内容是否读取成功：

uploaded_file = request.FILES["file"]
# 打印文件信息，验证是否获取到有效文件
print(f"文件名: {uploaded_file.name}, 文件大小: {uploaded_file.size}")
image_content = uploaded_file.read()
# 检查读取内容长度，若为0则说明读取失败
print(f"读取内容长度: {len(image_content)}")

• 不要硬编码MIME类型，改用文件自身的content_type：

raw_document=documentai.RawDocument(
    content=image_content, 
    mime_type=uploaded_file.content_type
)

4. 确认表单字段配置正确 #

检查UploadReceiptForm中的文件字段是否为FileField，示例配置：

from django import forms

class UploadReceiptForm(forms.Form):
    file = forms.FileField(label="上传收据文件")

完整修复后的代码片段 #

def upload(request):
    template_name = "upload.html"

    if request.method == "POST":
        form = UploadReceiptForm(request.POST, request.FILES)
        
        if form.is_valid():
            docai_client = documentai.DocumentProcessorServiceClient(
                client_options=ClientOptions(
                    api_endpoint=globals.GOOGLE_CLOUD_DOCUMENT_AI_ENDPOINT
                )
            )

            name = docai_client.processor_version_path(
                globals.GOOGLE_CLOUD_PROJECT_ID, 
                globals.GOOGLE_CLOUD_DEFAULT_LOCATION, 
                globals.GOOGLE_CLOUD_DEFAULT_PROCESSOR_ID, 
                globals.GOOGLE_CLOUD_DEFAULT_PROCESSOR_VERSION_ID
            )
            
            uploaded_file = request.FILES["file"]
            image_content = uploaded_file.read()
            
            docai_request = documentai.ProcessRequest(
                name=name,
                raw_document=documentai.RawDocument(
                    content=image_content, 
                    mime_type=uploaded_file.content_type
                ),
            )

            result = docai_client.process_document(request=docai_request)
            
            return HttpResponseRedirect("/upload/")

    else:
        form = UploadReceiptForm()

    return render(request, template_name, {"form": form})

内容的提问来源于stack exchange，提问作者SeaSky