Begin working on new core Fred class

fred/__init__.py

@@ -1,3 +1 @@
-from fred import Fred
-
-__all__ = [Fred]
+from core import Fred

fred/api.py

@@ -2,6 +2,13 @@
 Simplified functions for using the Fred API.
 """
 
+from .core import Fred
+
+
+def key(api_key):
+    os.environ['FRED_API_KEY'] = api_key
+
+
 #####################
 # Category
 #####################

fred/core.py

@@ -0,0 +1,116 @@
+"""
+FRED API documentation: http://api.stlouisfed.org/docs/fred/
+
+Core functionality for interacting with the FRED API.
+"""
+
+import os
+from itertools import ifilter
+
+import requests
+from relaxml import xml
+
+
+class Fred(object):
+    """An easy-to-use Python wrapper over the St. Louis FRED API."""
+
+    def __init__(self, api_key='', xml_output=False):
+        if 'FRED_API_KEY' in os.environ:
+            self.api_key = os.environ['FRED_API_KEY']
+        else:
+            self.api_key = api_key
+        self.xml = xml_output
+        self.endpoint = 'http://api.stlouisfed.org/fred/'
+
+    def _create_path(self, *args):
+        """Create the URL path with the Fred endpoint and given arguments."""
+        args = ifilter(None, args)
+        path = self.endpoint + '/'.join(args)
+        return path
+
+    def get(self, *args, **kwargs):
+        """Perform a GET request againt the Fred API endpoint."""
+        location = args[0]
+        params = self._get_keywords(location, kwargs)
+        url = self._create_path(args)
+        request = requests.get(url, params=params)
+        content = request.content
+        self._request = request
+        return self._output(content)
+
+    def _get_keywords(self, location, keywords):
+        """Format GET request's parameters from keywords."""
+        if 'xml' in keywords:
+            keywords.pop('xml')
+            self.xml = True
+        if 'id' in keywords:
+            if location != 'series':
+                location = location.rstrip('s')
+            key = '%s_id' % location
+            value = keywords.pop('id')
+            keywords[key] = value
+        if 'start' in keywords:
+            time = keywords.pop('start')
+            keywords['realtime_start'] = time
+        if 'end' in keywords:
+            time = keywords.pop('end')
+            keywords['realtime_end'] = time
+        if 'sort' in keywords:
+            order = keywords.pop('sort')
+            keywords['sort_order'] = order
+        keywords['api_key'] = self.api_key
+        return keywords
+
+    def _output(self, content):
+        """Return the output from a given GET request."""
+        if self.xml:
+            return content
+        return xml(content)
+
+    def category(self, child=None, **kwargs):
+        """
+        Get a specific category.
+
+        >>> Fred().category(category_id=125)
+        """
+        return self.get('category', child, **kwargs)
+
+    def releases(self, child=None, **kwargs):
+        """
+        Get all releases of economic data.
+
+        >>> Fred().releases('dates', limit=10)
+        """
+        return self.get('releases', child, **kwargs)
+
+    def release(self, child=None, **kwargs):
+        """
+        Get a release of economic data.
+
+        >>> Fred().release('series', release_id=51)
+        """
+        return self.get('release', child, **kwargs)
+
+    def series(self, child=None, **kwargs):
+        """
+        Get economic series of data.
+
+        >>> Fred().series('search', search_text="money stock")
+        """
+        return self.get('series', child, **kwargs)
+
+    def sources(self, child=None, **kwargs):
+        """
+        Get all of FRED's sources of economic data.
+
+        >>> Fred().sources()
+        """
+        return self.get('sources', child, **kwargs)
+
+    def source(self, child=None, **kwargs):
+        """
+        Get a single source of economic data.
+
+        >>> Fred().source(source_id=51)
+        """
+        return self.get('source', child, **kwargs)