preston 2.0.0

EVE CREST and XMLAPI access tool

Summary

Preston is a Python library for accessing EVE Online’s CREST API.

Installation

From pip:

pip install preston

Initialization

from preston.crest import Preston
# or
from preston.xmlapi import Preston


preston = Preston()

CREST

Attributes and calls

• Calling

• on preston.Preston: reload the base URL data

  • preston() -> the same preston.Preston

• on preston.APIElement: navigate to a new page

  • preston.foo() -> preston.APIElement

• Getting attribute by text or item by index

• from preston.Preston: return a data subset or navigate to a new page

  • preston.foo -> str, int, float, preston.APIElement of data subset, preston.APIElement to new page

• from preston.APIElement: return a data subset

  • preston.foo.bar -> str, int, float, preston.APIElement

To reduce typing, preston.Preston.__getattr__ combines the functionality of preston.APIElement.__getattr__ and preston.APIElement.__call__ so that calls can be made like preston.foo instead of preston().foo.

If you wanted to access the X position of the Kimoto constellation, the call would be:

preston.constellations().items.find(name='Kimotoro')().position.x

From the base url “constellations” is a root-level dictionary item with a “href” item, which can be called to navigate to that page.

From there, the .items attribute dives into the items dictionary key and then a find method is used to get an element from the list of dictionaries (you could loop through the items yourself, but find is for convenience). This dictionary has a “href” element, so call the attribute to navigate there.

Now on the final page, access the “position” key and finally its “x” key, which is -134996400468185440.

Examples

1. Market types -> page count

preston.marketTypes().pageCount

2. “Jump Through a Wormhole” opportunity description

preston.opportunities.tasks().items.find(name='Jump Through a Wormhole').description

3. Jita 4-4 moon name

preston.systems().items.find(name='Jita')().planets[3].moons[3]().name

Using the cache

When you make a call to preston.foo, the root CREST URL data stored locally will be checked for an expired cache timer (the root URL’s data is loaded when instantiating a new preston.Preston object, you don’t need to do it manually). If it’s expired, the root URL will be gotten anew and cached. This is similar for preston.foo().bar().baz() - if all of foo, bar, and baz were dictionaries with 'href' keys that pointed to new pages, each would use the cache to retrieve the page, only making a new request to CREST if the local copy of the page is either non-existent or expired.

However, when getting attributes from a page, like preston.foo().bar.baz, neither bar or baz on the page will be using the cache. Thus, in order to make the same call multiple times over a period of time and using the cache, either make the full preston.foo().bar.baz call again, or save the last-called element as a local variable and call that:

foo = preston.foo

print(foo().bar.baz)

# later:
print(foo().bar.baz)

# later:
print(foo().bar.baz)

Authentication

Accessing the authenticated parts of CREST is done through authenticating Preston:

from preston import *

preston = Preston(client_id='', client_secret='', client_callback='')
preston.get_authorize_url()
auth = preston.authenticate(code)

In the code above, get_authorize_url returns a URL to redirect a web app client to so they can log into EVE’s SSO. Once they’ve redirected back to your web application, pass the code in the returning URL from EVE to the authenticate call and assign the resulting preston.AuthPreston object.

This preston.AuthPreston object works the same as the unathenticated preston.Preston object: use attributes and calls to navigate and load CREST data, respectively.

Example of accessing a character’s location:

print(auth.decode().character().location())

Refresh tokens

When you authenticate for accessing CREST using a scope, Preston will get two tokens back: the access token, which is a temporary (20 minutes) token used for accessing CREST, and a refresh token that doesn’t expire but cannot be used to directly access CREST. When the access token expires, Preston will get another access token from CREST using the refresh token.

Since the refresh token doesn’t expire, you’ll want to keep that somewhere safe. Preston doesn’t handle this for you.

To start an authenticated session with Preston using a previously-fetched refresh token (you can get the existing refresh token with preston.AuthPreston.refresh_token as a str), do the following:

preston = Preston(client_id='', client_secret='', client_callback='')
auth = preston.use_refresh_token('previous-refresh-token')

XMLAPI

TODO