Wt  4.0.0
Installation: Unix-like platforms (Linux, macOS, BSD,...)
Wt Installation

Wt Installation instructions on Unix-like systems

This page lists the instructions for building and installing Wt on Unix-like systems (Linux, macOS, BSD,…). It is organized in 3 sections:

Requirements

The library provides two ways for deploying applications: either with the built-in web server (recommended), or using FastCGI (legacy).

The built-in web server is a simple HTTP and WebSockets server. It supports all of Wt's features, and is simple to setup. This is the recommended way of deploying a Wt application.

FastCGI is also supported if necessary, but it does not support WebSockets.

Each of these two choices correspond to a library, a so-called connector library. Below it is outlined how to configure the build process of Wt to build either or both libraries (libwthttp and libfcgi).

Thus, to build a Wt library with built-in web server you need to link against libwt and libwthttp. To build a Wt library which acts as a FastCGI process, you need to link against libwt and libfcgi.

1 Wt requirements

1a Using wthttpd

When using the built-in web server, two more libraries may be installed to enable optional features (you can also build without them), but otherwise no extra dependencies are required.

1b Using FastCGI

When using FastCGI, Wt requires a webserver (like Apache or NGINX) which supports the FastCGI protocol.

To build wtfcgi, you need:

2 Additional and optional requirements for some of the examples


Building and installing the Wt library

1. Create a build directory

The recommended way to build the library is in a separate build directory, for example within the top level of the Wt package:

    $ cd wt-x.x.x
    $ mkdir build
    $ cd build

2. Configure the library

    $ cmake ../

The latter command will try to locate the necessary libraries. If everything is OK, then this should end with something like:

  -- Generating done
  -- Build files have been written to: /home/kdforc0/project/wt/build

If CMake fails, because it cannot resolve all dependencies, then you may help CMake by setting some variables to help CMake locate the libraries. This may be done on the command-line using -Dvar=value or using the interactive program:

    $ ccmake ../
or
    $ cmake-gui ../

The GUI lists all variables that are configurable in Wt's build process.

The variables specify several build and configuration aspects of Wt, of which the most relevant ones are (there are many more visible in the GUI):

CMAKE_INSTALL_PREFIX
Installation prefix for the library and include files)
CONFIGDIR
Path for configuration files (default is /etc/wt/)
CONNECTOR_FCGI
Build the FastCGI connector (libwtfcgi) ?
CONNECTOR_HTTP
Build the stand-alone httpd connector (libwthttp) ?
EXAMPLES_CONNECTOR
Which connector library to use for the examples? (wthttp or wtfcgi)
MULTI_THREADED
Build a multi-threaded wthttpd? While on by default, and recommended, you may want to disable this for example if you suspect threading problems. Note that recursive event loops (most notably when using Dialog::exec()) are not possible without thread support.
The following variables apply to the FastCGI connector:
RUNDIR
Default location for Wt runtime session management (can be overridden in the Configuration file)
WEBUSER
Webserver username: used to assign permissions to RUNDIR
WEBGROUP
Webserver groupname: used to assign permissions to RUNDIR
The following variables apply to the wthttpd connector:
WTHTTP_CONFIGURATION
Location of the wthttpd configuration file (default is /etc/wt/wthttpd)
To change any entry, use [Enter]. To save and quit, do [c] followed by [g].

3. Build the library

    $ make
If you want to speed up compilation, you may want to use multiple threads (e.g. 4):
    $ make -j4

4. Install the library (as user with sufficient permissions):

    $ make install

5. Get your LD_LIBRARY_PATH ok, if needed (mostly for FastCGI).

If you did not install Wt in a directory (CMAKE_INSTALL_PREFIX) included in the default linker dynamic library search path, then the web server will not be able to start Wt programs (such as the examples).

Fix it by (as user with sufficient permissions):

    $ ln -s /your/path/to/lib/libwt.so /usr/lib
    $ ln -s /your/path/to/lib/libwtfcgi.so /usr/lib


Trying the examples (or your own Wt application)

Deploying an application is different when using FastCGI or the built-in web server (wthttpd).

The examples that come with the library use the connector specified by the build option EXAMPLES_CONNECTOR (see supra).

Some examples need TinyMCE:

You will notice 404 File not Found errors for resources/tiny_mce/ if you are missing this library.

A. Using wthttpd

1. Build the examples

    $ make -C examples

2. Running an example

Most examples use additional files, such as message resource bundles, which are not indicated with absolute path names. Therefore the working directory should be the source directory for the example. A similar argument goes for icons and the setting of the --docroot variable. Since Wt 3.1.4, you can use the "approot" property to move the additional files that should not be available to browsers outside of the docroot.

    $ cd ../examples/foobar # source directory for example foobar
    $ ln -s ../../resources . # include standard Wt resource files
    $ ../../build/examples/foobar/foobar.wt --docroot . --http-listen 0.0.0.0:8080

This will start a httpd server listening on all local interfaces, on port 8080, and you may browse the example at http://127.0.0.1:8080/

You will notice 404 File not Found errors for resources/ files if you are missing the resources files.

These are all the command-line options that are available:

General options:
  -h [ --help ]                         produce help message
  -t [ --threads ] arg (=-1)            number of threads (-1 indicates that
                                        num_threads from wt_config.xml is to be
                                        used, which defaults to 10)
  --servername arg                      servername (IP address or DNS name)
  --docroot arg                         document root for static files,
                                        optionally followed by a
                                        comma-separated list of paths with
                                        static files (even if they are within a
                                        deployment path), after a ';'

                                        e.g. --docroot=".;/favicon.ico,/resourc
                                        es,/style"

  --resources-dir arg                   path to the Wt resources folder. By
                                        default, Wt will look for its resources
                                        in the resources subfolder of the
                                        docroot (see --docroot). If a file is
                                        not found in that resources folder,
                                        this folder will be checked instead as
                                        a fallback. If this option is omitted,
                                        then Wt will not use a fallback
                                        resources folder.
  --approot arg                         application root for private support
                                        files; if unspecified, the value of the
                                        environment variable $WT_APP_ROOT is
                                        used, or else the current working
                                        directory
  --errroot arg                         root for error pages
  --accesslog arg                       access log file (defaults to stdout),
                                        to disable access logging completely,
                                        use --accesslog=-
  --no-compression                      do not use compression
  --deploy-path arg (=/)                location for deployment
  --session-id-prefix arg               prefix for session IDs (overrides
                                        wt_config.xml setting)
  -p [ --pid-file ] arg                 path to pid file (optional)
  -c [ --config ] arg                   location of wt_config.xml; if
                                        unspecified, the value of the
                                        environment variable $WT_CONFIG_XML is
                                        used, or else the built-in default
                                        (/etc/wt/wt_config.xml) is tried, or else
                                        built-in defaults are used
  --max-memory-request-size arg (=131072)
                                        threshold for request size (bytes), for
                                        spooling the entire request to disk, to
                                        avoid DoS
  --gdb                                 do not shutdown when receiving Ctrl-C
                                        (and let gdb break instead)

HTTP/WebSocket server options:
  --http-listen arg                     address/port pair to listen on. If no
                                        port is specified, 80 is used as the
                                        default, e.g. 127.0.0.1:8080 will cause
                                        the server to listen on port 8080 of
                                        127.0.0.1 (localhost). For IPv6, use
                                        square brackets, e.g. [::1]:8080 will
                                        cause the server to listen on port 8080
                                        of [::1] (localhost). This argument can
                                        be repeated, e.g. --http-listen
                                        0.0.0.0:8080 --http-listen [0::0]:8080
                                        will cause the server to listen on port
                                        8080 of all interfaces using IPv4 and
                                        IPv6. You must specify this option or
                                        --https-listen at least once. The older
                                        style --http-address and
                                        --https-address can also be used for
                                        backwards compatibility. If a hostname
                                        is provided instead of an IP address,
                                        the server will listen on all of the
                                        addresses (IPv4 and IPv6) that this
                                        hostname resolves to.
  --http-address arg                    IPv4 (e.g. 0.0.0.0) or IPv6 Address
                                        (e.g. 0::0). You must specify either
                                        --http-listen, --https-listen,
                                        --http-address, or --https-address.
  --http-port arg (=80)                 HTTP port (e.g. 80)

HTTPS/Secure WebSocket server options:
  --https-listen arg                    address/port pair to listen on. If no
                                        port is specified, 80 is used as the
                                        default, e.g. 127.0.0.1:8080 will cause
                                        the server to listen on port 8080 of
                                        127.0.0.1 (localhost). For IPv6, use
                                        square brackets, e.g. [::1]:8080 will
                                        cause the server to listen on port 8080
                                        of [::1] (localhost). This argument can
                                        be repeated, e.g. --https-listen
                                        0.0.0.0:8080 --https-listen [0::0]:8080
                                        will cause the server to listen on port
                                        8080 of all interfaces using IPv4 and
                                        IPv6. If a hostname is provided instead
                                        of an IP address, the server will
                                        listen on all of the addresses (IPv4
                                        and IPv6) that this hostname resolves
                                        to.
  --https-address arg                   IPv4 (e.g. 0.0.0.0) or IPv6 Address
                                        (e.g. 0::0). You must specify either
                                        --http-listen, --https-listen,
                                        --http-address, or --https-address.
  --https-port arg (=443)               HTTPS port (e.g. 443)
  --ssl-certificate arg                 SSL server certificate chain file
                                        e.g. "/etc/ssl/certs/vsign1.pem"
  --ssl-private-key arg                 SSL server private key file
                                        e.g. "/etc/ssl/private/company.pem"
  --ssl-tmp-dh arg                      File for temporary Diffie-Hellman
                                        parameters
                                        e.g. "/etc/ssl/dh512.pem"
  --ssl-enable-v3                       Switch on SSLv3 support (not
                                        recommended; disabled by default)
  --ssl-client-verification arg (=none) The verification mode for client
                                        certificates.
                                        This is either 'none', 'optional' or
                                        'required'. When 'none', the server
                                        will not request a client certificate.
                                        When 'optional', the server will
                                        request a certificate, but the client
                                        does not have to supply one. With
                                        'required', the connection will be
                                        terminated if the client does not
                                        provide a valid certificate.
  --ssl-verify-depth arg (=1)           Specifies the maximum length of the
                                        server certificate chain.

  --ssl-ca-certificates arg             Path to a file containing the
                                        concatenated trusted CA certificates,
                                        which can be used to authenticate the
                                        client. The file should contains a a
                                        number of PEM-encoded certificates.

  --ssl-cipherlist arg                  List of acceptable ciphers for SSL.
                                        This list is passed as-is to the SSL
                                        layer, so see openssl for the proper
                                        syntax. When empty, the default
                                        acceptable cipher list will be used.
                                        Example cipher list string:
                                        "TLSv1+HIGH:!SSLv2"

  --ssl-prefer-server-ciphers arg (=0)  By default, the client's preference is
                                        used for determining the cipher that is
                                        choosen during a SSL or TLS handshake.
                                        By enabling this option, the server's
                                        preference will be used.

B. Using FastCGI and apache

1. Build the examples

    $ make -C examples

2. Deploy the example foobar

The easiest way to deploy the examples is by copying the binary (from your build directory) and the source directory (which contains the images) and the resources/ into the same destination directory somewhere in your Apache server (we no longer generate a ./deploy.sh script that took care of some of this).

    $ export DESTINATION=/var/www/localhost/htdocs/wt-examples
    $ mkdir -p $DESTINATION/foobar
    $ cp -r examples/foobar/* resources/* build/examples/foobar/*.wt $DESTINATION/foobar/

This does however make public also files (such as message resources bundles, data files, etc...) that do not need to be served by your web server. The clean way to deploy your own applications is to use the "approot" property to deploy those files to a directory outside the webserver's doc root.

3. Configure Apache

Treat the example as a mod_fastcgi application, by adding a line to 20_mod_fastcgi.conf in your Apache configuration modules.d/ directory, e.g.:

    FastCgiServer /var/www/localhost/htdocs/wt-examples/composer/composer.wt

4. Restart apache


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