Using Proxies With C++ httplib in 2024

Jan 9, 2024 · 5 min read

Using a proxy with C++ httplib just takes a few extra lines.

You need to create a httplib::Client instance with the proxy host and port, rather than the target URL:

httplib::Client cli("proxy.com", 8000);

Then specify the full target URL on requests:

auto res = cli.Get("<https://www.example.com/page>");

Under the hood, httplib will route requests through the proxy server.

And voila! Your C++ application now has a proxy IP instead of the local machine's address.

You can also set the proxy directly on a client instance:

httplib::Client cli;
cli.set_proxy("proxy.com", 8000);

This separates proxy configuration from initialization. Handy for reusing the same client with different proxies.

Proxy Types

Not all proxies are made equal. Various types have tradeoffs in anonymity, speed, and data formats.

The most common proxy server protocols are:

  • HTTP - Sends data as regular HTTP requests. Easy to inspect payloads.
  • SOCKS - Generic proxy protocol for any TCP traffic. No payload inspection.
  • Transparent - Intercepts packets at router level. Challenging to detect proxy.
  • C++ httplib supports HTTP and SOCKS proxies. The syntax is the same as above.

    I suggest trying both to see which proxy providers offer the best performance and reliability for your use case.

    If you ever need transparent proxies, you'll likely set them up at the system level outside an app. But for most scraping jobs, HTTP or SOCKS gets it done!

    Dealing with Authentication

    Many proxy services require authentication to use their servers.

    C++ httplib lets you add username/password credentials so requests route successfully:

    httplib::Client cli;
    
    cli.set_proxy("proxy.com", 8000);
    cli.set_proxy_basic_auth("username", "password");
    
    auto res = cli.Get("<https://example.com>");
    

    The set_proxy_basic_auth() method handles adding the Proxy-Authorization header. This allows tunneling HTTPS content even with authentication in place.

    Some providers may use digest authentication instead, which has better security. To use this with httplib proxies:

    // Enable OpenSSL support for digest auth
    #define CPPHTTPLIB_OPENSSL_SUPPORT
    
    httplib::Client cli;
    
    cli.set_proxy("proxy.com", 8000);
    cli.set_proxy_digest_auth("username", "password");
    

    Just toggle the OpenSSL requirement and specify digest credentials. Then you can scrape securely!

    Chaining Multiple Proxies

    To take randomness even further, you can chain together multiple proxy servers:

    httplib::Client cli1;
    cli1.set_proxy("proxy1.com", 8000);
    
    httplib::Client cli2;
    cli2.set_proxy("proxy2.com", 8000);
    
    // Requests tunnel through both proxies
    if (auto res = cli1.Get("<https://website.com>", cli2)) {
      // ...
    }
    

    By passing a configured proxy client instance to request methods, you construct a chain. This adds more proxy hops for better anonymity.

    The chaining depth's up to you! But performance may suffer if overdone.

    Customizing Proxy Settings

    Beyond authentication and chaining, httpdlib lets you customize other useful proxy parameters:

    httplib::Client cli;
    
    // Timeout if proxy is idle after 10 sec
    cli.set_connection_timeout(0, 10);
    
    // Overall timeout if no proxy response after 30 sec
    cli.set_timeout(30);
    
    // Keep proxy connection alive for 4 requests
    cli.set_keep_alive(true, 4);
    

    Tweaking timeouts prevents problematic proxies from blocking requests. And adjusting keep-alive reuse reduces connection overhead.

    Play around to see what settings make your proxies shine! An ideal proxy strikes a balance of anonymity without slowness.

    Troubleshooting Proxy Issues

    Even with the best proxy setup, you'll inevitably hit snags. Server outages, connectivity drops, data errors, and more.

    Here are some common proxy problems I've debugged:

    Timeout errors - Set shorter timeout durations. Low-quality proxies tend to lag.

    SSL certificate issues - Some proxies don't tunnel HTTPS correctly. Try another provider.

    Failed requests - Authentication credentials may be invalid. Or the proxy IP was detected.

    Limited data - Proxy service likely has usage caps. Distribute requests over multiple proxies.

    Preemptively rotating multiple reliable proxies avoids headaches. But knowing these debug tips lets you troubleshoot confidently when issues do popup.

    When Proxies Come Up Short

    After all this proxy playtime with C++ httplib, an observation stands out.

    Proxy servers themselves have a single IP.

    No matter how I chain and rotate credentials, that last proxy link stays static. So scrapers can still get blocked if overused!

    I once had a sweet price checking scraper that helped snag online deal. But it kept getting stymied at certain stores after heavy usage from my proxy provider's IP range.

    There had to be a better way...

    Scraping Nirvana with Proxies API

    Just when proxy woes seemed inevitable, I have the perfect solution.

    Proxies API handles all the complex proxy orchestration behind a simple API call.

    It lets any C++ program mimic an ever-changing human visitor by automatically rotating:

  • IPs - Hundreds of thousands of proxies to prevent blocks
  • Locations - Regularly alternates proxy countries
  • Browsers - Changes user-agent to match valid browsers
  • You don't have to wrestle with authentication, custom configs, or debugging. The API abstracts it all!

    And CAPTCHAs or tricky Javascript pages render no problem through the built-in browsers.

    I just make requests like:

    curl "<http://api.proxiesapi.com/?key=XXX&url=https://target.com>"
    

    The rendered HTML, headers, status codes, and other metadata come back to parse. It's ideal for scrapers!

    No more proxy limitations and hours of management. I can focus time on handling the data.

    So when your proxy journey with C++ httplib starts feeling more hindrance than help, turn to Proxies API as the easy button for unblockable scraping!

    We have a running offer of 1000 API calls completely free. Register and get your free API Key here.

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