Source code for bulbs.rest

# -*- coding: utf-8 -*-
#
#James Thornton (http://jamesthornton.com)
# BSD License (see LICENSE for details)
#
"""
Low-level module for connecting to the Rexster REST server and
returning a Response object.

"""

import urllib
import urllib2
import httplib2
import simplejson as json
from urlparse import urlsplit
from posixpath import basename
import config

DEBUG = config.DEBUG
MAX_RETRIES = config.MAX_RETRIES

[docs]class Resource(object): """Used for connecting to the Rexster REST server.""" def __init__(self,db_url): """ Initializes a resource object. :param db_url: the base URL of Rexster. """ self.db_url = db_url if db_url.endswith("/"): # strip off trailing slash db_url = db_url[:-1] url_object = urlsplit(db_url) self.base_url = "%s://%s" % (url_object.scheme,url_object.netloc) self.db_name = basename(url_object.path)

[docs] def get(self,target,params): """Convenience method that sends GET requests to the resource.""" return self.request("GET",target,params)

[docs] def post(self,target,params): """Convenience method that sends POST requests to the resource.""" return self.request("POST",target,params)

[docs] def delete(self,target,params): """Convenience method that sends DELETE requests to the resource.""" return self.request("DELETE",target,params)

[docs] def request(self, method, target, params): """ Sends requests to the resource. :param method: either GET, POST, or DELETE. :param target: the URL path relative to the database URL you specified in either config.py or that you passed in as an argument when you instantiated the resource. :param params a dict of query-string parameters to include in the URL """ assert method in ("GET","POST","DELETE"), \ "Only GET, POST, DELETE are allowed." headers = {'Accept': 'application/json'} # httplib2 let's you cache http responses with memcache # really cool, look into that later # http = httplib2.Http(memcache) # the indicies condition is a hack until you implement # list type for indices keys if params and method is "POST" and "indices" not in target: url = self._build_url(method, target, params=None) body = urllib.urlencode(params) post_headers = {'Content-type': 'application/x-www-form-urlencoded'} headers.update(post_headers) else: url = self._build_url(method, target, params) body = None if DEBUG: print "REST url: ", url print "REST body: ", body attempt = 0 ok = False http = httplib2.Http() while not ok and (attempt < MAX_RETRIES): resp = Response(http.request(url, method, body, headers)) attempt += 1 ok = resp.ok # TODO: check http_status for 401s #assert resp.ok == True # TODO: if resp.http_status == 200, # else (where to put this?...maybe better at a higher level) return resp

def _build_url(self, method, target, params): """Used internally to construct the complete URL to the service.""" if type(target) == unicode: target = target.encode("utf8") url = "%s/%s" % (self.base_url, urllib2.quote(target)) if params: url = "%s?%s" % (url, urllib.urlencode(params)) return url

[docs]class Response(object): """A container for the Rexster HTTP response.""" def __init__(self, http_resp): """ NOTE: headers is a httplib2 Response object, content is a string see http://httplib2.googlecode.com/hg/doc/html/libhttplib2.html """ headers, content = http_resp self._response_handler(headers) if DEBUG: # only set raw if DEBUG=True to save on memory self.raw = http_resp try: self.headers = headers # don't save content on the resp object else you'll bloat it content = json.loads(content) self.ok = True # true if he response was returned from the cache self.fromcache = headers.fromcache # version of HTTP that the server supports. A value of 11 means 1.1 self.http_version = headers.version # numerical HTTP status code returned in the response self.http_status = headers.status # human readable component of the HTTP response status code self.http_reason = headers.reason # previous response object if redirects are followed self.http_previous = headers.previous # # header values not set in resp object but stored in the dict # # URI that was ultimately requested self.content_location = self.headers.get('content-location') self.tansfer_encoding = self.headers.get('transfer-encoding') self.server = self.headers.get('server') self.date = self.headers.get('date') self.allow_origin = self.headers.get('access-control-allow-origin') self.content_type = self.headers.get('content-type') # # body values always returned by reXster # self.rexster_version = content.get('version') self.query_time = content.get('queryTime') if self.query_time: self.query_time = float(self.query_time) # # body values sometimes returned, depending on resource requested # # if results is returned, it's a list of dicts, and # the dicts can contain any number of key/value pairs depending on # what is stored in each item -- items can be a node,edge... self.success = bool(content.get('success')) if "results" in content and type(content['results']) == list: self.results = iter(content['results']) else: self.results = content.get('results') self.index_name = content.get('name') self.index_class = content.get('class') self.index_type = content.get('type') self.total_size = content.get('totalSize') except ValueError: # looks like this isn't json, data is None self.ok = False def _response_handler(self,headers): """TODO: handle response errors.""" # Is there a list of error codes Rexster sends? # Pputting this in element won't work b/c element doesn't get the full # resp anymore, just results. Prob relegate to an resp/error helper pass