Module: TRMNLP::TransformBackend::Wrapper

Defined in:
lib/trmnlp/transform_backend/wrapper.rb

Overview

Code wrappers shared by Subprocess and Http backends. Each method emits the canonical dispatch harness — read stdin → run user code → find run/transform/result/passthrough → serialize output — and delegates the final write to a language-appropriate ‘output_sink` snippet supplied by the caller. Subprocess writes to a tempfile path, Http writes to FD 3 for the production daemon to capture.

Mirrors the hosted serverless runtime’s code-wrapping behavior, parameterized on the per-backend output sink. PHP additionally carries a leading ‘<?php` tag the file-based Subprocess path needs; the daemon tolerates it, so parity holds.

NOTE: ‘output_sink` is spliced verbatim into the generated script as executable code. It MUST be trmnlp-generated (see Subprocess#sink_for and Http#sink_for) and never derived from user input or config — an attacker-influenced sink is arbitrary code execution in the transform process. Only `code` is untrusted; the sink is part of the harness.

Class Method Summary collapse

Class Method Details

.for(language, code, output_sink) ⇒ Object 



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# File 'lib/trmnlp/transform_backend/wrapper.rb', line 105

def for(language, code, output_sink)
  case language.to_s
  when 'python' then python(code, output_sink)
  when 'ruby'   then ruby(code, output_sink)
  when 'node'   then node(code, output_sink)
  when 'php'    then php(code, output_sink)
  end
end

.node(code, output_sink) ⇒ Object

NOTE: node also accepts ‘function transform(input)` for production parity. Plugins authored against the hosted service using `transform` would otherwise silently pass input through.



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# File 'lib/trmnlp/transform_backend/wrapper.rb', line 63

def node(code, output_sink)
  <<~JS
    const input = JSON.parse(require('fs').readFileSync(0, 'utf8'));

    #{code}

    let output;
    if (typeof run === "function") {
      output = run(input);
    } else if (typeof transform === "function") {
      output = transform(input);
    } else if (typeof result !== "undefined") {
      output = result;
    } else {
      output = input;
    }
    #{output_sink}
  JS
end

.php(code, output_sink) ⇒ Object

NOTE: strips a leading ‘<?php` tag from user code so plugin authors can write the file as a standalone .php script. The hosted service does the same.



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# File 'lib/trmnlp/transform_backend/wrapper.rb', line 86

def php(code, output_sink)
  cleaned = code.sub(/\A\s*<\?php\s*/, '')
  <<~PHP
    <?php
    $input = json_decode(file_get_contents('php://stdin'), true);

    #{cleaned}

    if (function_exists('run')) {
        $output = run($input);
    } elseif (isset($result)) {
        $output = $result;
    } else {
        $output = $input;
    }
    #{output_sink}
  PHP
end

.python(code, output_sink) ⇒ Object 



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# File 'lib/trmnlp/transform_backend/wrapper.rb', line 25

def python(code, output_sink)
  <<~PYTHON
    import sys, json, os
    input = json.loads(sys.stdin.read())

    #{code}

    if callable(locals().get('run', None)):
        output = run(input)
    elif 'result' in dir():
        output = result
    else:
        output = input
    #{output_sink}
  PYTHON
end

.ruby(code, output_sink) ⇒ Object 



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# File 'lib/trmnlp/transform_backend/wrapper.rb', line 42

def ruby(code, output_sink)
  <<~RUBY
    require 'json'
    input = JSON.parse($stdin.read)

    #{code}

    output = if defined?(run) == 'method'
               run(input)
             elsif defined?(result)
               result
             else
               input
             end
    #{output_sink}
  RUBY
end