The Instructor HTTP client API offers extensive configuration options to customize client behavior for different scenarios. This chapter explores how to configure clients through configuration files and at runtime.

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Configuration Files

The primary configuration files for the HTTP client are:

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Main Configuration: config/http.php

This file defines the available client types and their settings: 
return [
    'defaultClient' => 'guzzle',
    'clients' => [
        'guzzle' => [
            'httpClientType' => 'guzzle',
            'connectTimeout' => 3,
            'requestTimeout' => 30,
            'idleTimeout' => -1,
            'maxConcurrent' => 5,
            'poolTimeout' => 60,
            'failOnError' => true,
        ],
        'symfony' => [
            'httpClientType' => 'symfony',
            'connectTimeout' => 1,
            'requestTimeout' => 30,
            'idleTimeout' => -1,
            'maxConcurrent' => 5,
            'poolTimeout' => 60,
            'failOnError' => true,
        ],
        'laravel' => [
            'httpClientType' => 'laravel',
            'connectTimeout' => 1,
            'requestTimeout' => 30,
            'idleTimeout' => -1,
            'maxConcurrent' => 5,
            'poolTimeout' => 60,
            'failOnError' => true,
        ],
    ],
];

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Debug Configuration: config/debug.php

This file controls debugging options for HTTP requests and responses: 
return [
    'http' => [
        'enabled' => false, // enable/disable debug
        'trace' => false, // dump HTTP trace information
        'requestUrl' => true, // dump request URL to console
        'requestHeaders' => true, // dump request headers to console
        'requestBody' => true, // dump request body to console
        'responseHeaders' => true, // dump response headers to console
        'responseBody' => true, // dump response body to console
        'responseStream' => true, // dump stream data to console
        'responseStreamByLine' => true, // dump stream as full lines or raw chunks
    ],
];

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Loading Configuration Files

The library uses a settings management system to load these configurations. The system looks for these files in the base directory of your project. If you’re using a framework like Laravel or Symfony, you can integrate with their configuration systems instead. For Laravel, you might publish these configurations as Laravel config files: 
php artisan vendor:publish --tag=polyglot-config
For Symfony, you might define these as service parameters in your service configuration.

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Configuration Options

The HttpClientConfig class encapsulates the configuration options for HTTP clients. Here’s a detailed breakdown of the available options:

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Basic Connection Options

OptionTypeDescriptionDefault
httpClientTypestringType of HTTP client to use'guzzle'
connectTimeoutintConnection timeout in seconds3
requestTimeoutintRequest timeout in seconds30
idleTimeoutintIdle timeout in seconds (-1 for no timeout)-1

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Request Pool Options

OptionTypeDescriptionDefault
maxConcurrentintMaximum number of concurrent requests in a pool5
poolTimeoutintTimeout for the entire request pool in seconds60

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Error Handling Options

OptionTypeDescriptionDefault
failOnErrorboolWhether to throw exceptions on HTTP errorstrue

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Debug Options

OptionTypeDescriptionDefault
enabledboolEnable or disable HTTP debuggingfalse
traceboolDump HTTP trace informationfalse
requestUrlboolLog the request URLtrue
requestHeadersboolLog request headerstrue
requestBodyboolLog request bodytrue
responseHeadersboolLog response headerstrue
responseBodyboolLog response bodytrue
responseStreamboolLog streaming response datatrue
responseStreamByLineboolLog stream as complete lines (true) or raw chunks (false)true

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Understanding Timeout Options

Timeout settings are crucial for controlling how your application handles slow or unresponsive servers:
  • connectTimeout: Maximum time to wait for establishing a connection to the server. If the server doesn’t respond within this time, the request fails with a connection timeout error. Setting this too low might cause failures when connecting to slow servers, but setting it too high could leave your application waiting for unresponsive servers.
  • requestTimeout: Maximum time to wait for the entire request to complete, from connection initiation to receiving the complete response. If the entire request-response cycle isn’t completed within this time, the request fails with a timeout error.
  • idleTimeout: Maximum time to wait between receiving data packets. If the server stops sending data for longer than this period, the connection is considered idle and is terminated. Setting this to -1 disables the idle timeout, which is useful for long-running streaming connections.
  • poolTimeout: Maximum time to wait for all requests in a pool to complete. If any requests in the pool haven’t completed within this time, they’re terminated.

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Runtime Configuration

While configuration files provide a static way to configure clients, you often need to change configuration at runtime based on the specific requirements of a request or operation.

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Using withClient

The simplest way to switch configurations at runtime is to use the withClient method to select a different pre-configured client: 
// Start with default client
$client = new HttpClient();

// Switch to a client with longer timeouts
$client->withClient('guzzle-long-timeout');

// Switch to a client optimized for streaming
$client->withClient('guzzle-streaming');

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Using withConfig

For more dynamic configuration, you can create a custom HttpClientConfig object and apply it using the withConfig method: 
use Cognesy\Http\Config\HttpClientConfig;

// Create a custom configuration
$config = new HttpClientConfig(
    driver: 'guzzle',
    connectTimeout: 5,
    requestTimeout: 60,
    idleTimeout: 30,
    maxConcurrent: 10,
    poolTimeout: 120,
    failOnError: false
);

// Use the custom configuration
$client->withConfig($config);
This method gives you complete control over the configuration at runtime.

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Creating Configuration from an Array

You can also create a configuration from an associative array: 
$configArray = [
    'httpClientType' => 'symfony',
    'connectTimeout' => 2,
    'requestTimeout' => 45,
    'idleTimeout' => -1,
    'maxConcurrent' => 8,
    'poolTimeout' => 90,
    'failOnError' => true,
];

$config = HttpClientConfig::fromArray($configArray);
$client->withConfig($config);
This approach is useful when loading configuration from external sources like environment variables or configuration files.

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Enabling Debug Mode

You can enable debug mode to see detailed information about requests and responses: 
// Enable debug mode
$client->withDebugPreset('on');

// Make a request
$response = $client->withRequest($request)->get();

// Disable debug mode when done
$client->withDebugPreset('off');
When debug mode is enabled, detailed information about requests and responses is output to the console or log.

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Example: Dynamic Configuration Based on Request Type

Here’s an example of dynamically adjusting configuration based on the type of request: 
function configureClientForRequest(HttpClient $client, HttpRequest $request): HttpClient {
    // Get the current configuration
    $config = HttpClientConfig::load($client->getClientName());

    // Adjust timeouts based on the request URL
    if (strpos($request->url(), 'large-file') !== false) {
        // For large file downloads, use longer timeouts
        $config = new HttpClientConfig(
            httpClientType: $config->httpClientType,
            connectTimeout: $config->connectTimeout,
            requestTimeout: 300, // 5 minutes
            idleTimeout: 60,     // 1 minute
            maxConcurrent: $config->maxConcurrent,
            poolTimeout: $config->poolTimeout,
            failOnError: $config->failOnError
        );

        $client->withConfig($config);
    }

    // Enable streaming for specific endpoints
    if (strpos($request->url(), '/stream') !== false || strpos($request->url(), '/events') !== false) {
        // Make sure the request is set to stream
        $request = $request->withStreaming(true);
    }

    // Enable debug for development environment
    if (getenv('APP_ENV') === 'development') {
        $client->withDebugPreset('on');
    }

    return $client;
}

// Usage
$client = new HttpClient();
$request = new HttpRequest(...);

// Configure the client based on the request
$client = configureClientForRequest($client, $request);

// Send the request
$response = $client->withRequest($request)->get();
This approach allows for highly dynamic and contextual configuration adjustments.

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Configuration Best Practices

  1. Define Base Configurations in Files: Keep your common configurations in the config/http.php file for easy reference and maintenance.
  2. Use Named Configurations: Create named configurations for different scenarios (e.g., 'guzzle-short-timeout', 'guzzle-streaming') to make your code more readable and maintainable.
  3. Adjust Timeouts Appropriately: Set timeouts based on the expected response time of the API or service you’re calling. Shorter for quick operations, longer for file uploads/downloads or streaming.
  4. Consider Error Handling Strategy: Set failOnError based on how you want to handle errors. For critical operations, set it to true to catch errors immediately. For bulk operations or request pools, set it to false to handle errors individually.
  5. Use Debug Mode Judiciously: Enable debug mode only when needed, as it can generate a lot of output and potentially impact performance.
  6. Test Different Configurations: Experiment with different settings to find the optimal configuration for your specific use cases.

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Adapting to Different Environments

Different environments often require different configurations. Here’s how you might handle this: 
// In your application bootstrap or service provider
function configureHttpClient() {
    $env = getenv('APP_ENV') ?: 'production';

    // Load base configuration
    $config = HttpClientConfig::load('guzzle');

    // Adjust based on environment
    switch ($env) {
        case 'development':
            // Shorter timeouts for faster feedback during development
            $config = new HttpClientConfig(
                httpClientType: $config->httpClientType,
                connectTimeout: 1,
                requestTimeout: 10,
                idleTimeout: $config->idleTimeout,
                maxConcurrent: $config->maxConcurrent,
                poolTimeout: $config->poolTimeout,
                failOnError: true // Throw errors for immediate feedback
            );
            break;

        case 'testing':
            // Use mock driver for tests
            $config = new HttpClientConfig(
                httpClientType: 'custom',
                connectTimeout: 1,
                requestTimeout: 1,
                idleTimeout: 1,
                maxConcurrent: 1,
                poolTimeout: 5,
                failOnError: true
            );

            // Create a mock client
            $mockDriver = new MockHttpDriver();
            // Configure mock responses...

            return (new HttpClient())->withConfig($config)->withDriver($mockDriver);

        case 'production':
            // More conservative timeouts for production
            $config = new HttpClientConfig(
                httpClientType: $config->httpClientType,
                connectTimeout: 5,
                requestTimeout: 60,
                idleTimeout: $config->idleTimeout,
                maxConcurrent: 10,
                poolTimeout: 120,
                failOnError: false // Handle errors gracefully in production
            );
            break;
    }

    return (new HttpClient())->withConfig($config);
}

// Get a properly configured client
$client = configureHttpClient();
This approach allows you to adapt your HTTP client configuration to different environments while maintaining a consistent API. In the next chapter, we’ll explore how to create and use custom HTTP client implementations for specialized needs.