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Debugging Plugins

This guide covers techniques and tools for debugging Movian plugins.

Debug Logging

Enable Plugin Debug Mode

Run Movian with plugin debugging:

movian --debug plugin

Console Logging

Use console.log() in your plugin:

console.log("Debug message:", variable);
console.log("Object:", JSON.stringify(obj, null, 2));

Log Levels

console.log("Info message");
console.warn("Warning message");
console.error("Error message");

Common Issues

Plugin Not Loading

Check:

  1. plugin.json is valid JSON
  2. Plugin ID is unique
  3. File paths are correct
  4. Movian logs for errors

Debug:

movian --debug plugin --trace

JavaScript Errors

Symptoms:

  • Plugin crashes
  • Functions not working
  • Unexpected behavior

Debug:

try {
  // Your code
} catch(e) {
  console.error("Error:", e.message);
  console.error("Stack:", e.stack);
}

HTTP Request Failures

Debug HTTP requests (API v2):

var http = require('movian/http');

try {
  var response = http.request(url, {
    method: 'GET',
    debug: true  // Enable HTTP debugging
  });
  console.log("Response:", response.toString());
} catch(e) {
  console.error("HTTP Error:", e.message);
}

Page Not Rendering

Check:

  1. Route pattern matches URL
  2. page.loading = false is set
  3. Items are added correctly
  4. No JavaScript errors

Debug:

new page.Route("plugin:page", function(page) {
  console.log("Route handler called");

  page.type = "directory";
  console.log("Page type set");

  page.appendItem("url", "video", {title: "Test"});
  console.log("Item added");

  page.loading = false;
  console.log("Loading complete");
});

Debugging Techniques

Breakpoint Simulation

function debugBreakpoint(message) {
  console.log("=== BREAKPOINT ===");
  console.log(message);
  console.log("=================");
}

debugBreakpoint("Before API call");
var result = apiCall();
debugBreakpoint("After API call: " + JSON.stringify(result));

Variable Inspection

function inspect(obj, name) {
  console.log("=== " + name + " ===");
  for (var key in obj) {
    console.log(key + ":", obj[key]);
  }
  console.log("================");
}

inspect(page, "Page Object");
inspect(page.metadata, "Page Metadata");

Timing Analysis

var startTime = Date.now();

// Your code here

var endTime = Date.now();
console.log("Execution time:", (endTime - startTime) + "ms");

Network Debugging

var http = require('movian/http');

function debugHttpRequest(url, options) {
  console.log("HTTP Request:", url);
  console.log("Options:", JSON.stringify(options));

  var start = Date.now();
  try {
    var response = http.request(url, options);
    var duration = Date.now() - start;

    console.log("Response received in", duration + "ms");
    console.log("Status:", response.statuscode);
    console.log("Headers:", JSON.stringify(response.headers));

    return response;
  } catch(e) {
    console.error("Request failed:", e.message);
    throw e;
  }
}

Testing Strategies

Unit Testing

Create test functions:

function testParseData() {
  var input = '{"test": "data"}';
  var result = parseData(input);

  if (result.test === "data") {
    console.log("✓ testParseData passed");
  } else {
    console.error("✗ testParseData failed");
  }
}

// Run tests
testParseData();

Integration Testing

Test complete workflows:

function testVideoPlayback() {
  console.log("Testing video playback...");

  // Create test page
  new page.Route("test:video", function(page) {
    page.type = "directory";
    page.appendItem("test:play:1", "video", {
      title: "Test Video"
    });
    page.loading = false;
  });

  console.log("Test route created");
}

Log Analysis

Find Plugin Logs

Linux/macOS: 

tail -f ~/.hts/movian/log

Windows: 

type %APPDATA%\Movian\log

Filter Logs

grep "plugin:myplugin" ~/.hts/movian/log

Common Error Patterns

Syntax Error: 

SyntaxError: Unexpected token

Reference Error: 

ReferenceError: variable is not defined

Type Error: 

TypeError: Cannot read property 'x' of undefined

Best Practices

Defensive Programming

function safeAccess(obj, path) {
  var parts = path.split('.');
  var current = obj;

  for (var i = 0; i < parts.length; i++) {
    if (!current || typeof current !== 'object') {
      return undefined;
    }
    current = current[parts[i]];
  }

  return current;
}

// Usage
var title = safeAccess(data, 'metadata.title') || 'Unknown';

Error Boundaries

function withErrorHandling(fn) {
  return function() {
    try {
      return fn.apply(this, arguments);
    } catch(e) {
      console.error("Error in", fn.name, ":", e.message);
      return null;
    }
  };
}

// Usage
var safeFunction = withErrorHandling(riskyFunction);

Validation

function validateConfig(config) {
  var errors = [];

  if (!config.apiKey) {
    errors.push("Missing apiKey");
  }

  if (!config.baseUrl) {
    errors.push("Missing baseUrl");
  }

  if (errors.length > 0) {
    console.error("Configuration errors:", errors.join(", "));
    return false;
  }

  return true;
}

Tools

JSON Validator

function isValidJSON(str) {
  try {
    JSON.parse(str);
    return true;
  } catch(e) {
    console.error("Invalid JSON:", e.message);
    return false;
  }
}

URL Validator

function isValidUrl(url) {
  var pattern = /^https?:\/\/.+/;
  if (!pattern.test(url)) {
    console.error("Invalid URL:", url);
    return false;
  }
  return true;
}

Performance Debugging

Memory Usage

Monitor object creation:

var objectCount = 0;

function createObject() {
  objectCount++;
  console.log("Objects created:", objectCount);
  return {};
}

Request Optimization

var http = require('movian/http');
var requestCache = {};

function cachedRequest(url) {
  if (requestCache[url]) {
    console.log("Cache hit:", url);
    return requestCache[url];
  }

  console.log("Cache miss:", url);
  var response = http.request(url);
  requestCache[url] = response;
  return response;
}

See Also