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HTTP Server


This sample application demonstrates the use of the HTTP Server library. This library provides high-level functions to simplify and abstract server implementation. The server supports the HTTP/1.1 protocol which can also be upgraded to HTTP/2, it also support native HTTP/2 protocol without upgrading.


QEMU Networking

Building and running the server

To build and run the application:

$ west build -p auto -b <board_to_use> -t run samples/net/sockets/http_server

When the server is up, we can make requests to the server using either HTTP/1.1 or HTTP/2 protocol from the host machine.

With HTTP/1.1:

  • Using a browser:

  • Using curl: curl -v --compressed

  • Using ab (Apache Bench): ab -n10

With HTTP/2:

  • Using nghttp client: nghttp -v --no-dep

  • Using curl: curl --http2 -v --compressed

  • Using h2load: h2load -n10

Server Customization

The server sample contains several parameters that can be customized based on the requirements. These are the configurable parameters:

  • CONFIG_NET_SAMPLE_HTTP_SERVER_SERVICE_PORT: Configures the service port.

  • CONFIG_HTTP_SERVER_MAX_CLIENTS: Defines the maximum number of HTTP/2 clients that the server can handle simultaneously.

  • CONFIG_HTTP_SERVER_MAX_STREAMS: Specifies the maximum number of HTTP/2 streams that can be established per client.

  • CONFIG_HTTP_SERVER_CLIENT_BUFFER_SIZE: Defines the buffer size allocated for each client. This limits the maximum length of an individual HTTP header supported.

  • CONFIG_HTTP_SERVER_MAX_URL_LENGTH: Specifies the maximum length of an HTTP URL that the server can process.

  • CONFIG_NET_SAMPLE_WEBSOCKET_SERVICE: Enables Websocket service endpoint. This allows a Websocket client to connect to / endpoint, all the data that the client sends is echoed back.

To customize these options, we can run west build -t menuconfig, which provides us with an interactive configuration interface. Then we could navigate from the top-level menu to: -> Subsystems and OS Services -> Networking -> Network Protocols.

Websocket Connectivity

You can use a simple Websocket client application like this to test the Websocket connectivity.

import websocket

ws = websocket.WebSocket()
ws.send("Hello, Server")
while True:
  line = input("> ")
  if line == "quit":

Performance Analysis

CPU Usage Profiling

We can use perf to collect statistics about the CPU usage of our server running in native_sim board with the stat command:

$ sudo perf stat -p <pid_of_server>

perf stat will then start monitoring our server. We can let it run while sending requests to our server. Once we’ve collected enough data, we can stop perf stat, which will print a summary of the performance statistics.

Hotspot Analysis

perf record and perf report can be used together to identify the functions in our code that consume the most CPU time:

$ sudo perf record -g -p <pid_of_server> -o

After running our server under load (For example, using ApacheBench tool), we can stop the recording and analyze the data using:

$ sudo perf report -i

After generating a file named which contains the profiling data, we can visualize it using FlameGraph tool. It’s particularly useful for identifying the most expensive code-paths and inspect where our application is spending the most time.

To do this, we need to convert the to a format that FlameGraph can understand:

$ sudo perf script | ~/FlameGraph/ > out.perf-folded

And, then, generate the FlameGraph:

$ ~/FlameGraph/ out.perf-folded > flamegraph.svg

We can view flamegraph.svg using a web browser.