HTTP Server¶

Overview¶

The HTTP Server sample application for Zephyr implements a basic TCP server on top of the HTTP Server Library that is able to receive HTTP 1.1 requests, parse them and write back the responses.

The source code for this sample application can be found at: samples/net/http_server.

Requirements¶

Linux machine with wget and the screen terminal emulator
Either QEMU or real device like Freedom Board (FRDM-K64F)
For QEMU see this Networking with QEMU
LAN for testing purposes (Ethernet)

Building and Running¶

Currently, the HTTP Server application is configured to listen at port 80. If you want to modify the http-server sample application, please check the configuration settings in samples/net/http_server/src/main.c file and also in the samples/net/http_server/src/config.h file.

To use QEMU for testing, follow the Networking with QEMU guide.

This sample code supports both static and dynamic (DHCPv4) IP addresses that can be defined in the project configuration file:

CONFIG_NET_CONFIG_MY_IPV6_ADDR="2001:db8::1"
CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"

Adding URLs¶

To define a new URL or to change how a URL is processed by the HTTP server, open the samples/net/http_server/src/main.c file and locate the following lines:

http_server_add_default(&http_urls, default_handler);
http_server_add_url(&http_urls, "/headers", HTTP_URL_STANDARD);
http_server_add_url(&http_urls, "/index.html", HTTP_URL_STANDARD);

The first line defines how Zephyr will deal with unknown URLs. In this case, it will respond with a soft HTTP 404 status code, i.e. an HTTP 200 OK status code with a 404 Not Found HTML body.

To build this sample on your Linux host computer, open a terminal window, locate the source code of this sample application and type:

cd $ZEPHYR_BASE/samples/net/http_server
mkdir build && cd build
cmake -GNinja -DBOARD=qemu_x86 ..
ninja run

Sample Output¶

Assume in this example that this HTTP server is configured to listen at IPv4 address 192.168.1.120 and IPv6 address 2001:db8::1 port 80. On your Linux host computer, open a terminal window and type:

wget 192.168.1.120/index.html

wget will show:

--2017-01-17 00:37:44--  http://192.168.1.120/
Connecting to 192.168.1.120:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: 'index.html'

The HTML file generated by Zephyr and downloaded by wget is:

<html>
<head>
<title>Zephyr HTTP Server</title>
</head>
<body><h1><center>It Works!</center></h1></body>
</html>

The screen application will display the following information:

[http-server] [DBG] http_connected: (0x00403fa0): HTTP connect attempt URL /index.html
[http-server] [DBG] http_serve_index_html: (0x00403fa0): Sending index.html (170 bytes) to client
[http-server] [DBG] http_closed: (0x00403fa0): Connection 0x004004c0 closed

To obtain the HTTP Header Fields web page, use the following command:

wget 192.168.1.120/headers -O index.html

wget will show:

--2017-01-19 22:09:55--  http://192.168.1.120/headers
Connecting to 192.168.1.120:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: 'index.html'

This is the HTML file generated by Zephyr and downloaded by wget:

<html>
<head>
<title>Zephyr HTTP Server</title>
</head>
<body>
<h1>Zephyr HTTP server</h1>
<h2>HTTP Header Fields</h2>
<ul>
<li>User-Agent: Wget/1.16 (linux-gnu)</li>
<li>Accept: */*</li>
<li>Host: 192.168.1.120</li>
<li>Connection: Keep-Alive</li>
</ul>
<h2>HTTP Method: GET</h2>
<h2>URL: /headers</h2>
<h2>Server: arm</h2>
</body>
</html>

To test the 404 Not Found soft error, use the following command:

wget 192.168.1.120/not_found -O index.html

Zephyr will generate an HTTP response with the following header:

HTTP/1.1 200 OK
Content-Type: text/html
Transfer-Encoding: chunked

and this is the HTML message that wget will save:

<html>
<head>
<title>Zephyr HTTP Server</title>
</head>
<body><h1><center>404 Not Found</center></h1></body>
</html>

HTTPS Server¶

The sample code also includes a HTTPS (HTTP over TLS) server example running side by side with the HTTP server, this server runs on QEMU. In order to compile and run the code execute:

cd $ZEPHYR_BASE/samples/net/http_server
mkdir build && cd build
cmake -GNinja -DBOARD=qemu_x86 -DCONF_FILE=prj_tls.conf ..
ninja run

Known Issues and Limitations¶

Currently, this sample application only generates HTTP responses in chunk transfer mode.