unoserver
Using LibreOffice as a server for converting documents.
Overview
Using LibreOffice to convert documents is easy, you can use a command like this to convert a file to PDF, for example:
$ libreoffice --headless --convert-to pdf ~/Documents/MyDocument.odf
However, that will load LibreOffice into memory, convert a file and then exit LibreOffice, which means that the next time you convert a document LibreOffice needs to be loaded into memory again.
To avoid that, LibreOffice has a listener mode, where it can listen for commands via a port, and load and convert documents without exiting and reloading the software. This lowers the CPU load when converting many documents with somewhere between 50% and 75%, meaning you can convert somewhere between two and four times as many documents in the same time using a listener.
Unoserver contains three commands to help you do this, unoserver which starts a listener on the specified IP interface and port, and unoconverter which will connect to a listener and ask it to convert a document, as well as unocompare which will connect to a listener and ask it to compare two documents and convert the result document.
Installation
NB! Windows and Mac support is as of yet untested.
Unoserver needs to be installed by and run with the same Python installation that LibreOffice uses. On Unix this usually means you can just install it with:
$ sudo pip install unoserver
If you have multiple versions of LibreOffice installed, you need to install it for each one. Usually each LibreOffice install will have it's own python executable and you need to run pip with that executable:
$ sudo /full/path/to/python -m pip install unoserver
To find all Python installations that have the relevant LibreOffice libraries installed, you can run a script called find_uno.py:
wget -O find_uno.py https://gist.githubusercontent.com/regebro/036da022dc7d5241a0ee97efdf1458eb/raw/find_uno.py python3 find_uno.py
This should give an output similar to this:
Trying python found at /usr/bin/python3... Success! Trying python found at /opt/libreoffice7.1/program/python... Success! Found 2 Pythons with Libreoffice libraries: /usr/bin/python3 /opt/libreoffice7.1/program/python
The /usr/bin/python3 binary will be the system Python used for versions of Libreoffice installed by the system package manager. The Pythons installed under /opt/ will be Python versions that come with official LibreOffice distributions.
To install on such distributions, do the following:
$ wget https://bootstrap.pypa.io/get-pip.py $ sudo /path/to/python get-pip.py $ sudo /path/to/python -m pip install unoserver
You can also install it in a virtualenv, if you are using the system Python
for that virtualenv, and specify the --system-site-packages parameter:
$ virtualenv --python=/usr/bin/python3 --system-site-packages virtenv $ virtenv/bin/pip install unoserver
Windows and Mac installs aren't officially supported yet, but on Windows the paths to the LibreOffice Python executable are usually in locations such as C:\Program Files (x86)\LibreOffice\python.exe. On Mac it can be for example /Applications/LibreOffice.app/Contents/python.
Usage
Installing unoserver installs three scripts, unoserver, unoconverter and unocompare. All can also be run as modules with python3 -m unoserver.server, python3 -m unoserver.converter and python3 -m unoserver.comparer with the same arguments as the main scripts.
Unoserver
unoserver [-h] [--interface INTERFACE] [--port PORT] [--daemon] [--executable EXECUTABLE]
- --interface: The interface used by the server, defaults to "localhost"
- --port: The port used by the server, defaults to "2002"
- --daemon: Deamonize the server
- --executable: The path to the LibreOffice executable
Unoconvert
unoconvert [-h] [--convert-to CONVERT_TO] [--filter FILTER_NAME] [--interface INTERFACE] [--port PORT] infile outfile
- infile: The path to the file to be converted (use - for stdin)
- outfile: The path to the converted file (use - for stdout)
- --convert-to: The file type/extension of the output file (ex pdf). Required when using stdout
- --filter: The export filter to use when converting. It is selected automatically if not specified.
- --interface: The interface used by the server, defaults to "localhost"
- --port: The port used by the server, defaults to "2002"
Unocompare
unocompare [-h] [--convert-to CONVERT_TO] [--interface INTERFACE] [--port PORT] infile inorigfile outfile
- infile: The path to the modified file to be compared with the original one (use - for stdin)
- inorigfile: The path to the original file to be compared with the modified one (use - for stdin)
- outfile: The path to the result of the comparison and converted file (use - for stdout)
- --convert-to: The file type/extension of the output file (ex pdf). Required when using stdout
- --interface: The interface used by the server, defaults to "localhost"
- --port: The port used by the server, defaults to "2002"
Development and Testing
Clone the repo from https://github.com/unoconv/unoserver.
Setup a virtualenv:
$ virtualenv --system-site-packages ve $ ve/bin/pip install -e .[devenv]
Run tests:
$ ve/bin/pytest tests
Run flake8 linting:
$ ve/bin/flake8 src tests
Comparison with unoconv
Unoserver started as a rewrite, and hopefully a replacement to unoconv, a module with support for using LibreOffice as a listener to convert documents.
Differences for the user
- Easier install for system versions of LibreOffice. On Linux, the packaged versions of LibreOffice typically uses the system Python, making it easy to install unoserver with a simple sudo pip install unoserver command.
- Separate commands for server and client. The client no longer tries to start a listener and then close it after conversion if it can't find a listener. Instead the new unoconverter client requires the unoserver to be started. This makes it less practical for one-off converts, but as mentioned that can easily be done with LibreOffice itself.
- The unoserver listener does not prevent you from using LibreOffice as a normal user, while the unoconv listener would block you from starting LibreOffice to open a document normally.
- You should be able to on a multi-core machine run several unoservers with different ports. There is however no support for any form of load balancing in unoserver, you would have to implement that yourself in your usage of unoconverter.
- Only LibreOffice is officially supported. Other variations are untested.
Differences for the maintainer
- It's a complete and clean rewrite, supporting only Python 3, with easier to understand and therefore easier to maintain code, hopefully meaning more people can contribute.
- It doesn't rely on internal mappings of file types and export filters, but asks LibreOffice for this information, which will increase compatibility with different LibreOffice versions, and also lowers maintenance.