Installing wkhtmltopdf on Linux can be a bit tricky, especially for people who are not so familiar with *nix operating systems. There are various ways in which you can install wkhtmltopdf; use a package manager such as apt-get, compile from source, or download the pre-compiled binary file. We are going to be doing the latter in this tutorial.
Now the installation instructions for wkhtmltopdf have changed over the years, but as of this writing, the commands that you are about to see work for Ubuntu 14.04 and Ubuntu 16.04.
Installing wkhtmltopdf Dependencies
First, we need to install a couple of wkhtmltopdf dependencies.
apt-get install libfontconfig \ zlib1g \ libfreetype6 \ libxrender1 \ libxext6 \ libx11-6
Downloading & Extracting Archive
Then we will download and extract an archive containing the binary file. Be sure to update the link to use whichever version you prefer. You can find the links on the download page over at wkhtmltopdf.org.
curl -L -o wkhtmltopdf.tar.xz https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.4/wkhtmltox-0.12.4_linux-generic-amd64.tar.xz tar -xf wkhtmltopdf.tar.xz
Moving Binary File & Permissions
Now we have a directory named wkhtmltox within our current working directory. This directory contains the binary file that we are looking for within the bin directory, namely wkhtmltopdf. We could just use that binary file from that directory as is, but we probably want to make wkhtmltopdf available throughout the system. To do that, we need to move it and give it permission to execute.
mv wkhtmltox/bin/wkhtmltopdf /usr/local/bin/wkhtmltopdf chmod +x /usr/local/bin/wkhtmltopdf
Fixing SSL Bug
Now as of this writing, there is an issue causing you to see output similar to this when using wkhtmltopdf.
Loading pages (1/6) QSslSocket: cannot resolve CRYPTO_num_locks ] 10% QSslSocket: cannot resolve CRYPTO_set_id_callback QSslSocket: cannot resolve CRYPTO_set_locking_callback QSslSocket: cannot resolve sk_free QSslSocket: cannot resolve sk_num ... ... ...
This relates to resolving SSL, so the solution is currently to downgrade libssl and
openssl. There may be other solutions, but this is what I found to be working. Now this is really not ideal, so hopefully it will be fixed soon. Until then, if you need to install wkhtmltopdf in a production setup, then please consider the implications of downgrading, such as security considerations.
Either way, here is how to fix the problem. Be sure to run the commands as root, e.g. with sudo.
For Ubuntu 14.04:
apt-get install openssl=1.0.1f-1ubuntu2.22 apt-get install libssl-dev=1.0.1f-1ubuntu2.22
For Ubuntu 16.04:
apt-get install libssl1.0.0=1.0.2g-1ubuntu4.8 apt-get install libssl-dev=1.0.2g-1ubuntu4.8
Running wkhtmltopdf now, the above errors should go away and everything should be working.
You can test if wkhtmltopdf is working as intended by generating a PDF file with contents of google.com.
wkhtmltopdf https://www.google.com google.pdf
I will try to stay up to date with any changes, but these things change quite often. So if the above does not work out for you, please let me know in the comments.