Rails 5.2 Rest API + Active Storage - 上传从外部服务接收的文件blob

Question

我们正在从外部服务接收POST调用，该服务包含文件blob（以Base64编码）和一些其他参数。

# POST call to /document/:id/document_data
param = {
    file: <base64 encoded file blob>
}

我们希望处理该文件并将其上传到以下模型

# MODELS
# document.rb  
class Document < ApplicationRecord
    has_one_attached :file
end

我们希望上传blob，而无需写入磁盘上的实际文件，然后上传它。

Answer 1

在处理POST调用的Controller方法中

# documents_controller.rb - this method handles POST calls on /document/:id/document_data

def document_data

  # Process the file, decode the base64 encoded file
  @decoded_file = Base64.decode64(params["file"])

  @filename = "document_data.pdf"            # this will be used to create a tmpfile and also, while setting the filename to attachment
  @tmp_file = Tempfile.new(@filename)        # This creates an in-memory file 
  @tmp_file.binmode                          # This helps writing the file in binary mode.
  @tmp_file.write @decoded_file
  @tmp_file.rewind()

  # We create a new model instance 
  @document = Document.new
  @document.file.attach(io: @tmp_file, filename: @filename) # attach the created in-memory file, using the filename defined above
  @document.save

  @tmp_file.unlink # deletes the temp file
end

希望这可以帮助。

有关Tempfile的更多信息，请访问here。