casimport/README.md

casimport
=========

This is a python module that is designed to load Python code from a
cryptographic hash.  The idea is that instead of having to package
up simple code as a Python package, you can import it directly via
the hash.

There is the concept of aliases to make the import statements easier
to read.  This is currently limited to packages.  An example is the
randpkg in the fixtures directory.  You can put a file named
cas_aliases.txt along side your __init__.py file.  Each line of the
file is:
```
<alias>	<url>
```

Where alias is a simple name, and url is a location to find the file
at.  Currently, at least one hash url must be specified.

The following url schemes are supported:
<dl>
<dt>hash</dt>
<dd>At least one of these MUST be specified. This is specified at
[hash-uri](https://github.com/hash-uri/hash-uri) and currently only
a hash value of sha256 is supported.</dd>
<dt>ipfs</dt>
<dd>The format follows the
[IPFS Addressing](https://github.com/ipfs/in-web-browsers/blob/master/ADDRESSING.md)
document, and it is recommend that CIDv1 addresses are used, as the
host portion of a URL is case insensitive, and CIDv0 (the current
default) values are case sensitive.  An example is:
`ipfs://bafkreibtbcckul7lwxqz7nyzj3dknhwrdxj5o4jc6gsroxxjhzz46albym`.</dd>
<dt>https</dt>
<dd>This is the standard web url that everyone is familar with.</dd>
</dl>

Usage
-----

Top level usage:
```
import casimport
from cas.v1_f_330884aa2febb5e19fb7194ec6a69ed11dd3d77122f1a5175ee93e73cf0161c3 import hello

print(repr(hello('Alice')))
```

Defintion of module names in cas package:
v<num>_<type>_<arg>

Currently v1 is defined, and has the following types:
	f	The arg is the hash of the Python source file.
		Example generated via: shasum -a 256 hello.py
	a	An alias.  Any aliases must be loaded before being
		processed.  This is a short name that could be used.

Configuration
-------------

By default, a configuration file is read from `~/.casimport/casimport.conf`.
This specifies the priority of the different modules (do you search IPFS or
HTTPS urls first), and configures each of the modules.

The first time you import casimport, a sample configuration will be created.
The default is a local cache the home directory, and then to use IPFW
gateway, followed by normal https urls.