pycapnp/README.md
2013-09-04 10:38:00 -07:00

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#pycapnp
More thorough docs are available at [http://jparyani.github.io/pycapnp/](http://jparyani.github.io/pycapnp/).
## Requirements
First you need a system-wide installation of the Cap'n Proto C++ library >= 0.3. Follow the [official installation docs](http://kentonv.github.io/capnproto/install.html) or for the lazy:
```bash
curl -O http://capnproto.org/capnproto-c++-0.3.0.tar.gz
tar zxf capnproto-c++-0.3.0.tar.gz
cd capnproto-c++-0.3.0
./configure
make -j6 check
sudo make install
```
A recent version of cython and setuptools is also required. You can install these with:
```bash
pip install -U cython
pip install -U setuptools
```
## Building and installation
Install with `pip install pycapnp`. You can set the CC environment variable to control which compiler is used, ie `CC=gcc-4.8 pip install pycapnp`.
Or you can clone the repo like so:
git clone https://github.com/jparyani/pycapnp.git
`cd` into the repo directory and run `pip install .`
## Development
This project uses [git-flow](http://jeffkreeftmeijer.com/2010/why-arent-you-using-git-flow/). Essentially, just make sure you do your changes in the `develop` branch. You can run the tests by installing pytest with `pip install pytest`, and then run `py.test`
## Documentation/Example
There is some basic documentation [here](http://jparyani.github.io/pycapnp/).
The examples directory has one example that shows off the capabilities quite nicely. Here it is, reproduced:
```python
from __future__ import print_function
import os
import capnp
import addressbook_capnp
def writeAddressBook(file):
addresses = addressbook_capnp.AddressBook.new_message()
people = addresses.init('people', 2)
alice = people[0]
alice.id = 123
alice.name = 'Alice'
alice.email = 'alice@example.com'
alicePhones = alice.init('phones', 1)
alicePhones[0].number = "555-1212"
alicePhones[0].type = 'mobile'
alice.employment.school = "MIT"
bob = people[1]
bob.id = 456
bob.name = 'Bob'
bob.email = 'bob@example.com'
bobPhones = bob.init('phones', 2)
bobPhones[0].number = "555-4567"
bobPhones[0].type = 'home'
bobPhones[1].number = "555-7654"
bobPhones[1].type = 'work'
bob.employment.unemployed = None
addresses.write(file)
def printAddressBook(file):
addresses = addressbook_capnp.AddressBook.read(file)
for person in addresses.people:
print(person.name, ':', person.email)
for phone in person.phones:
print(phone.type, ':', phone.number)
which = person.employment.which()
print(which)
if which == 'unemployed':
print('unemployed')
elif which == 'employer':
print('employer:', person.employment.employer)
elif which == 'school':
print('student at:', person.employment.school)
elif which == 'selfEmployed':
print('self employed')
print()
if __name__ == '__main__':
f = open('example', 'w')
writeAddressBook(f)
f = open('example', 'r')
printAddressBook(f)
```
## Common Problems
If you get an error on installation like:
...
gcc-4.8: error: capnp/capnp.c: No such file or directory
gcc-4.8: fatal error: no input files
Then you have too old a version of setuptools. Run `pip install -U setuptools` then try again.
[![Build Status](https://travis-ci.org/jparyani/pycapnp.png?branch=develop)](https://travis-ci.org/jparyani/pycapnp)