Vix.cpp

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Compression Middleware Guide ​

What is HTTP Compression? ​

Compression reduces the size of HTTP responses before sending them to the client.

Benefits:

  • Faster network transfer
  • Lower bandwidth usage
  • Better performance on mobile or slow connections

In Vix.cpp, compression is middleware-based and automatic.

How Compression Works ​

  1. Client sends: Accept-Encoding: gzip, br

  2. Server checks:

    • Is compression enabled?
    • Is response size >= min_size?
    • Does client support compression?

  3. If yes:

    • Response is compressed
    • Vary header is added (if enabled)

Minimal Example ​

cpp
App app;

auto mw = vix::middleware::app::adapt_ctx(
    vix::middleware::performance::compression({
        .min_size = 8,
        .add_vary = true,
        .enabled = true,
    }));

app.use(std::move(mw));

app.get("/x", [](Request&, Response& res)
{
    res.send(std::string(20, 'a'));
});

app.run(8080);

Run ​

bash
vix run compression_app_simple.cpp

Test With curl ​

1) No Accept-Encoding ​

bash
curl -i http://localhost:8080/x

Result: No compression applied.

2) With Accept-Encoding ​

bash
curl -i -H "Accept-Encoding: gzip, br" http://localhost:8080/x

If body is large enough: Compression is applied.

3) Small body (below min_size) ​

bash
curl -i -H "Accept-Encoding: gzip" http://localhost:8080/small

No compression because body < min_size.

Important Options ​

.min_size Minimum response size required to compress.

.enabled Enable or disable compression.

.add_vary Adds: Vary: Accept-Encoding

This is important for proper caching behavior.

Complete Working Example ​

Save as: compression_app_simple.cpp

cpp
#include <iostream>
#include <string>
#include <vix.hpp>

#include <vix/middleware/app/adapter.hpp>
#include <vix/middleware/performance/compression.hpp>

using namespace vix;

int main()
{
    App app;

    // Install compression globally
    auto mw = vix::middleware::app::adapt_ctx(
        vix::middleware::performance::compression({
            .min_size = 8,
            .add_vary = true,
            .enabled = true,
        }));

    app.use(std::move(mw));

    app.get("/", [](Request&, Response& res)
    {
        res.send("Compression middleware installed.");
    });

    // Large body (should compress if client supports it)
    app.get("/x", [](Request&, Response& res)
    {
        res.status(200).send(std::string(20, 'a'));
    });

    // Small body (no compression)
    app.get("/small", [](Request&, Response& res)
    {
        res.status(200).send("aaaa");
    });

    app.run(8080);
    return 0;
}

Summary ​

Compression middleware:

  • Automatically checks Accept-Encoding
  • Compresses only when useful
  • Keeps your code clean
  • Improves performance without changing route logic

Vix.cpp keeps compression simple and explicit.