From d582ac9cc7fe9026d534d242ca17a6a191e473c2 Mon Sep 17 00:00:00 2001
From: Chris Mague <maguec@users.noreply.github.com>
Date: Tue, 20 Oct 2020 00:29:57 -0700
Subject: [PATCH] Add FT.alias functionality (#99)

* index alias add

* add tests for v < 2.0 on aliases

* search 2.0 handles aliases differently
---
 redisearch/client.py | 38 ++++++++++++++++++++
 test/test.py         | 82 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 120 insertions(+)

diff --git a/redisearch/client.py b/redisearch/client.py
index 55b05f9..2686dd8 100644
--- a/redisearch/client.py
+++ b/redisearch/client.py
@@ -174,6 +174,9 @@ class Client(object):
     MGET_CMD = 'FT.MGET'
     CONFIG_CMD = 'FT.CONFIG'
     TAGVALS_CMD = 'FT.TAGVALS'
+    ALIAS_ADD_CMD = 'FT.ALIASADD'
+    ALIAS_UPDATE_CMD = 'FT.ALIASUPDATE'
+    ALIAS_DEL_CMD = 'FT.ALIASDEL'
 
     NOOFFSETS = 'NOOFFSETS'
     NOFIELDS = 'NOFIELDS'
@@ -659,3 +662,38 @@ def tagvals(self, tagfield):
         cmd = self.redis.execute_command(self.TAGVALS_CMD, self.index_name, tagfield)
         return cmd
 
+    def aliasadd(self, alias):
+        """
+        Alias a search index - will fail if alias already exists
+
+        ### Parameters
+
+        - **alias**: Name of the alias to create
+        """
+
+        cmd = self.redis.execute_command(self.ALIAS_ADD_CMD, alias, self.index_name)
+        return cmd
+
+    def aliasupdate(self, alias):
+        """
+        Updates an alias - will fail if alias does not already exist
+
+        ### Parameters
+
+        - **alias**: Name of the alias to create
+        """
+
+        cmd = self.redis.execute_command(self.ALIAS_UPDATE_CMD, alias, self.index_name)
+        return cmd
+
+    def aliasdel(self, alias):
+        """
+        Removes an alias to a search index
+
+        ### Parameters
+
+        - **alias**: Name of the alias to delete
+        """
+
+        cmd = self.redis.execute_command(self.ALIAS_DEL_CMD, alias)
+        return cmd
\ No newline at end of file
diff --git a/test/test.py b/test/test.py
index 12fde7d..feefe44 100644
--- a/test/test.py
+++ b/test/test.py
@@ -564,6 +564,88 @@ def testSummarize(self):
             self.assertEqual('ACT I SCENE I. London. The palace. Enter <b>KING</b> <b>HENRY</b>, LORD JOHN OF LANCASTER, the EARL of WESTMORELAND, SIR... ',
                             doc.txt)
 
+    def testAlias(self):
+        conn = self.redis()
+        with conn as r:
+            if check_version_2(r):
+
+                index1 = Client('testAlias', port=conn.port)
+                index1.redis.flushdb()
+                index2 = Client('testAlias2', port=conn.port)
+
+                index1.redis.hset("index1:lonestar", mapping = {'name': 'lonestar'})
+                index2.redis.hset("index2:yogurt", mapping = {'name': 'yogurt'})
+
+                time.sleep(2)
+
+                def1 =IndexDefinition(prefix=['index1:'],score_field='name')
+                def2 =IndexDefinition(prefix=['index2:'],score_field='name')
+                
+                index1.create_index((TextField('name'),),definition=def1)
+                index2.create_index((TextField('name'),),definition=def2)
+
+                res = index1.search('*').docs[0]
+                self.assertEqual('index1:lonestar', res.id)
+
+                # create alias and check for results
+                index1.aliasadd("spaceballs")
+                alias_client = Client('spaceballs', port=conn.port)
+                res = alias_client.search('*').docs[0]
+                self.assertEqual('index1:lonestar', res.id)
+
+                # We should throw an exception when trying to add an alias that already exists
+                with self.assertRaises(Exception) as context:
+                    index2.aliasadd('spaceballs')
+                self.assertEqual('Alias already exists', str(context.exception))
+
+                #update alias and ensure new results
+                index2.aliasupdate("spaceballs")
+                alias_client2 = Client('spaceballs', port=conn.port)
+                res = alias_client2.search('*').docs[0]
+                self.assertEqual('index2:yogurt', res.id)
+
+                index2.aliasdel("spaceballs")
+                with self.assertRaises(Exception) as context:
+                    alias_client2.search('*').docs[0]
+                self.assertEqual('spaceballs: no such index', str(context.exception))
+                
+            else:
+
+                # Creating a client with one index
+                index1 = Client('testAlias', port=conn.port)
+                index1.redis.flushdb()
+
+                index1.create_index((TextField('txt'),))
+                index1.add_document('doc1', txt = 'text goes here')
+
+                index2 = Client('testAlias2', port=conn.port)
+                index2.create_index((TextField('txt'),))
+                index2.add_document('doc2', txt = 'text goes here')
+
+
+                # add the actual alias and check
+                index1.aliasadd('myalias')
+                alias_client = Client('myalias', port=conn.port)
+                res = alias_client.search('*').docs[0]
+                self.assertEqual('doc1', res.id)
+
+                # We should throw an exception when trying to add an alias that already exists
+                with self.assertRaises(Exception) as context:
+                    index2.aliasadd('myalias')
+                self.assertEqual('Alias already exists', str(context.exception))
+
+                # update the alias and ensure we get doc2
+                index2.aliasupdate('myalias')
+                alias_client2 = Client('myalias', port=conn.port)
+                res = alias_client2.search('*').docs[0]
+                self.assertEqual('doc2', res.id)
+
+                # delete the alias and expect an error if we try to query again
+                index2.aliasdel('myalias')
+                with self.assertRaises(Exception) as context:
+                    alias_client2.search('*').docs[0]
+                self.assertEqual('myalias: no such index', str(context.exception))
+
     def testTags(self):
         conn = self.redis()