CODEWITHSUNDEEP
javaprotocol-buffers
Prasath
Prasath

Reputation: 1284

Protobuffers to XML

I want to convert my google protocol object to XML format. In that I would like to keep some fields as attribute. Instead of : 

<field>
    <name>ApiFieldHeaderName</name>
    <maxLength>50</maxLength>
</field>

I want following :

<field name="ApiFieldHeaderName" maxLength="50" ></field>

My protocol is 

string name = 1;
int32 maxLength = 2;

And then I have gone through some forum and used xml_disposition

[(xml_disposition) = ATTRIBUTE]

However, I am getting the error:

Option "(xml_disposition)" unknown.

I am using proto3 and language is Java.

syntax = "proto3";
option optimize_for = SPEED;

Upvotes: 1

Views: 1990

Answers (1)

Marc Gravell
Marc Gravell

Reputation: 1063864

I believe you've found xml_disposition from a side discussion on the protobuf newsgroup from 2009. The option mentioned, however, was purely hypothetical. As far as I know: no such xml_disposition custom option exists - and least, not as a standard option - and no code-generator looks for it. No mention of xml_disposition exists in the Google protobuf source, and the current version of protoc (3.5.1) does not recognise it and an inbuilt option.

So:

  • yes, it is possible to add custom extensions in .proto that you can annotate fields (etc) with
  • yes, you can write your own codegen tools to check for those custom options and emit additional generated code to implement what you want
  • but none of this ships by default

Side note: custom options must be defined in "proto2" syntax files, but a "proto3" file can still import and use those custom options from the "proto2" file.

Upvotes: 1

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