#capnpc-python-cpp
More thorough docs are available at http://jparyani.github.io/capnpc-python-cpp/.
First you need a system-wide installation of the Cap'n Proto C++ library >= 0.3. Unfortunately, as of now, that means you have to build from the HEAD of Cap'n Proto. Follow these instructions to do so:
wget https://github.com/kentonv/capnproto/archive/master.zip
unzip master.zip
cd capnproto-master/c++
./setup-autotools.sh
autoreconf -i
./configure
make -j6 check
sudo make install
sudo ldconfig
A recent version of cython and setuptools is also required. You can install these with:
pip install -U cython
pip install -U setuptools
Install with pip install capnp
Or you can clone the repo like so:
git clone https://github.com/jparyani/capnpc-python-cpp.git
cd
into the repo directory and run pip install .
There is some basic documentation here.
The examples directory has one example that shows off the capabilities quite nicely. Here it is, reproduced:
import capnp
addressbook = capnp.load('addressbook.capnp')
def writeAddressBook(fd):
message = capnp.MallocMessageBuilder()
addressBook = message.initRoot(addressbook.AddressBook)
people = addressBook.initPeople(2)
alice = people[0]
alice.id = 123
alice.name = 'Alice'
alice.email = '[email protected]'
alicePhones = alice.initPhones(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 = '[email protected]'
bobPhones = bob.initPhones(2)
bobPhones[0].number = "555-4567"
bobPhones[0].type = 'home'
bobPhones[1].number = "555-7654"
bobPhones[1].type = 'work'
bob.employment.unemployed = None
capnp.writePackedMessageToFd(fd, message)
f = open('example', 'w')
writeAddressBook(f.fileno())
def printAddressBook(fd):
message = capnp.PackedFdMessageReader(f.fileno())
addressBook = message.getRoot(addressbook.AddressBook)
for person in addressBook.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
f = open('example', 'r')
printAddressBook(f.fileno())
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.