from coreapi.codecs import default_decoders

from coreapi.compat import string_types

from coreapi.document import Document, Link

from coreapi.exceptions import LinkLookupError

from coreapi.transports import default_transports, determine_transport

import collections

import itypes

LinkAncestor = collections.namedtuple('LinkAncestor', ['document', 'keys'])

def _lookup_link(document, keys):

"""

Validates that keys looking up a link are correct.

Returns a two-tuple of (link, link_ancestors).

"""

if not isinstance(keys, (list, tuple)):

msg = "'keys' must be a list of strings or ints."

raise TypeError(msg)

if any([

not isinstance(key, string_types) and not isinstance(key, int)

for key in keys

]):

raise TypeError("'keys' must be a list of strings or ints.")

# Determine the link node being acted on, and its parent document.

# 'node' is the link we're calling the action for.

# 'document_keys' is the list of keys to the link's parent document.

node = document

link_ancestors = [LinkAncestor(document=document, keys=[])]

for idx, key in enumerate(keys):

try:

node = node[key]

except (KeyError, IndexError, TypeError):

index_string = ''.join('[%s]' % repr(key).strip('u') for key in keys)

msg = 'Index %s did not reference a link. Key %s was not found.'

raise LinkLookupError(msg % (index_string, repr(key).strip('u')))

if isinstance(node, Document):

ancestor = LinkAncestor(document=node, keys=keys[:idx + 1])

link_ancestors.append(ancestor)

# Ensure that we've correctly indexed into a link.

if not isinstance(node, Link):

index_string = ''.join('[%s]' % repr(key).strip('u') for key in keys)

msg = "Can only call 'action' on a Link. Index %s returned type '%s'."

raise LinkLookupError(

msg % (index_string, type(node).__name__)

)

return (node, link_ancestors)

class Client(itypes.Object):

def __init__(self, decoders=None, transports=None):

if decoders is None:

decoders = default_decoders

if transports is None:

transports = default_transports

self._decoders = itypes.List(decoders)

self._transports = itypes.List(transports)

@property

def decoders(self):

return self._decoders

@property

def transports(self):

return self._transports

def get(self, url):

link = Link(url, action='get')

# Perform the action, and return a new document.

transport = determine_transport(link.url, transports=self.transports)

return transport.transition(link, decoders=self.decoders)

def reload(self, document):

url = document.url

link = Link(url, action='get')

# Perform the action, and return a new document.

transport = determine_transport(link.url, transports=self.transports)

return transport.transition(link, decoders=self.decoders)

def action(self, document, keys, params=None, action=None, inplace=None):

if isinstance(keys, string_types):

keys = [keys]

# Validate the keys and link parameters.

link, link_ancestors = _lookup_link(document, keys)

if (action is not None) or (inplace is not None):

# Handle any explicit overrides.

action = link.action if (action is None) else action

inplace = link.inplace if (inplace is None) else inplace

link = Link(link.url, action, inplace, link.fields)

# Perform the action, and return a new document.

transport = determine_transport(link.url, transports=self.transports)

return transport.transition(link, params, decoders=self.decoders, link_ancestors=link_ancestors)