some work towards multilingual search

2 files changed, 317 insertions, 4 deletions

diff --git a/askbot/search/postgresql/__init__.py b/askbot/search/postgresql/__init__.py
index 4e359cc1..3edef65d 100644
--- a/askbot/search/postgresql/__init__.py
+++ b/askbot/search/postgresql/__init__.py
@@ -3,6 +3,26 @@ from django.db import connection
 from django.conf import settings as django_settings
 from django.utils.translation import get_language
 
+#mapping of "django" language names to postgres
+LANGUAGE_NAMES = {
+    'da': 'danish',
+    'nl': 'dutch',
+    'en': 'english',
+    'fi': 'finnish',
+    'fr': 'french',
+    'de': 'german',
+    'hu': 'hungarian',
+    'it': 'italian',
+    'ja': 'japanese',
+    'nb': 'norwegian',
+    'pt': 'portugese',
+    'ro': 'romanian',
+    'ru': 'russian',
+    'es': 'spanish',
+    'sv': 'swedish',
+    'tr': 'turkish'
+}
+
 def setup_full_text_search(script_path):
     """using postgresql database connection,
     installs the plsql language, if necessary
@@ -37,17 +57,21 @@ def run_full_text_search(query_set, query_text, text_search_vector_name):
  
     rank_clause = 'ts_rank(' + table_name + \
                     '.' + text_search_vector_name + \
-                    ', plainto_tsquery(%s))'
+                    ', plainto_tsquery(%s, %s))'
  
     where_clause = table_name + '.' + \
                     text_search_vector_name + \
-                    ' @@ plainto_tsquery(%s)'
+                    ' @@ plainto_tsquery(%s, %s)'
+
+    language_code = get_language()
 
     if getattr(django_settings, 'ASKBOT_MULTILINGUAL', True):
-        where_clause += " AND language_code='" + get_language() + "'"
+        where_clause += " AND " + table_name + \
+                        '.' + "language_code='" + language_code + "'"
 
     search_query = '&'.join(query_text.split())#apply "AND" operator
-    extra_params = (search_query,)
+    language_name = LANGUAGE_NAMES.get(language_code, 'english')
+    extra_params = (language_name, search_query,)
     extra_kwargs = {
         'select': {'relevance': rank_clause},
         'where': [where_clause,],
diff --git a/askbot/search/postgresql/thread_and_post_models_01022013.plsql b/askbot/search/postgresql/thread_and_post_models_01022013.plsql
new file mode 100644
index 00000000..8e57ed1b
--- /dev/null
+++ b/askbot/search/postgresql/thread_and_post_models_01022013.plsql
@@ -0,0 +1,289 @@
+/* function testing for existence of a column in a table
+   if table does not exists, function will return "false" */
+CREATE OR REPLACE FUNCTION column_exists(colname text, tablename text)
+RETURNS boolean AS 
+$$
+DECLARE
+    q text;
+    onerow record;
+BEGIN
+
+    q = 'SELECT attname FROM pg_attribute WHERE attrelid = ( SELECT oid FROM pg_class WHERE relname = '''||tablename||''') AND attname = '''||colname||''''; 
+
+    FOR onerow IN EXECUTE q LOOP
+        RETURN true;
+    END LOOP;
+
+    RETURN false;
+END;
+$$ LANGUAGE plpgsql;
+
+/* function adding tsvector column to table if it does not exists */
+CREATE OR REPLACE FUNCTION add_tsvector_column(colname text, tablename text)
+RETURNS boolean AS
+$$
+DECLARE
+    q text;
+BEGIN
+    IF NOT column_exists(colname, tablename) THEN
+        q = 'ALTER TABLE ' || tablename || ' ADD COLUMN ' || colname || ' tsvector';
+        EXECUTE q;
+        RETURN true;
+    ELSE
+        q = 'UPDATE ' || tablename || ' SET ' || colname || '=NULL';
+        EXECUTE q;
+        RETURN false;
+    END IF;
+END;
+$$ LANGUAGE plpgsql;
+
+/* aggregate function that concatenates tsvectors */
+CREATE OR REPLACE FUNCTION tsv_add(tsv1 tsvector, tsv2 tsvector)
+RETURNS tsvector AS
+$$
+BEGIN
+    RETURN tsv1 || tsv2;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE OR REPLACE FUNCTION setup_aggregates() RETURNS boolean AS
+$$
+DECLARE
+    onerow record;
+BEGIN
+    FOR onerow IN SELECT * FROM pg_proc WHERE proname = 'concat_tsvectors' AND proisagg LOOP
+        DROP AGGREGATE concat_tsvectors(tsvector);
+    END LOOP;
+    CREATE AGGREGATE concat_tsvectors (
+        BASETYPE = tsvector,
+        SFUNC = tsv_add,
+        STYPE = tsvector,
+        INITCOND = ''
+    );
+    RETURN true;
+END;
+$$ LANGUAGE plpgsql;
+
+SELECT setup_aggregates();
+
+/* language name resolution function. todo: move languace conv to python code */
+DROP FUNCTION IF EXISTS get_language_name_from_code(lang_code text);
+CREATE OR REPLACE FUNCTION get_language_name_from_code(lang_code text)
+RETURNS regconfig AS
+$$
+BEGIN
+    IF lang_code = 'en' THEN
+        RETURN 'english';
+    ELSIF lang_code = 'da' THEN
+        RETURN 'danish';
+    ELSIF lang_code = 'nl' THEN
+        RETURN 'danish';
+    ELSIF lang_code = 'fi' THEN
+        RETURN 'finnish';
+    ELSIF lang_code = 'fr' THEN
+        RETURN 'french';
+    ELSIF lang_code = 'de' THEN
+        RETURN 'german';
+    ELSIF lang_code = 'hu' THEN
+        RETURN 'hungarian';
+    ELSIF lang_code = 'it' THEN
+        RETURN 'italian';
+    ELSIF lang_code = 'nb' THEN
+        RETURN 'norwegian';
+    ELSIF lang_code = 'pt' THEN
+        RETURN 'portugese';
+    ELSIF lang_code = 'ro' THEN
+        RETURN 'romanian';
+    ELSIF lang_code = 'ru' THEN
+        RETURN 'russian';
+    ELSIF lang_code = 'es' THEN
+        RETURN 'spanish';
+    ELSIF lang_code = 'sv' THEN
+        RETURN 'swedish';
+    ELSIF lang_code = 'tr' THEN
+        RETURN 'turkish';
+    ELSIF lang_code = 'ja' THEN
+        RETURN 'japanese';
+    END IF;
+    RETURN 'english';
+END;
+$$ LANGUAGE plpgsql;
+
+/* calculates text search vector for the individual thread row
+DOES not include question body post, answers or comments */
+DROP FUNCTION IF EXISTS get_thread_tsv(title text, tagnames text);
+CREATE OR REPLACE FUNCTION get_thread_tsv(title text, tagnames text, lang_code text)
+RETURNS tsvector AS
+$$
+DECLARE
+    lang_name regconfig;
+BEGIN
+    lang_name = get_language_name_from_code(lang_code);
+    /* todo add weight depending on votes */
+    RETURN  setweight(to_tsvector(lang_name, coalesce(title, '')), 'A') ||
+            setweight(to_tsvector(lang_name, coalesce(tagnames, '')), 'A');
+END;
+$$ LANGUAGE plpgsql;
+
+/* calculates text seanch vector for the individual question row */
+DROP FUNCTION IF EXISTS get_post_tsv(text text, post_type text);
+CREATE OR REPLACE FUNCTION get_post_tsv(text text, post_type text, lang_code text)
+RETURNS tsvector AS
+$$
+DECLARE
+    lang_name regconfig;
+BEGIN
+    /* todo adjust weights to reflect votes */
+    lang_name = get_language_name_from_code(lang_code);
+    IF post_type='question' THEN
+        RETURN setweight(to_tsvector(lang_name, coalesce(text, '')), 'B');
+    ELSIF post_type='answer' THEN
+        /* todo reflect whether the answer acepted or has many points */
+        RETURN setweight(to_tsvector(lang_name, coalesce(text, '')), 'C');
+    ELSIF post_type='comment' THEN
+        RETURN setweight(to_tsvector(lang_name, coalesce(text, '')), 'D');
+    ELSE
+        RETURN to_tsvector('');
+    END IF;
+END;
+$$ LANGUAGE plpgsql;
+
+/* calculates text search vector for the question body part by thread id
+here we extract question title and the text by thread_id and then
+calculate the text search vector. In the future question
+title will be moved to the askbot_thread table and this function
+will be simpler.
+*/
+CREATE OR REPLACE FUNCTION get_thread_question_tsv(thread_id integer)
+RETURNS tsvector AS
+$$
+DECLARE
+    query text;
+    onerow record;
+BEGIN
+    query = 'SELECT text, language_code FROM askbot_post WHERE thread_id=' || thread_id ||
+            ' AND post_type=''question'' AND deleted=false';
+    FOR onerow in EXECUTE query LOOP
+        RETURN get_post_tsv(onerow.text, 'question', onerow.language_code);
+    END LOOP;
+    RETURN to_tsvector('');
+END;
+$$ LANGUAGE plpgsql;
+
+DROP FUNCTION IF EXISTS get_dependent_comments_tsv(object_id integer, tablename text);
+CREATE OR REPLACE FUNCTION get_dependent_comments_tsv(parent_id integer)
+RETURNS tsvector AS
+$$
+DECLARE
+    query text;
+    onerow record;
+BEGIN
+    query = 'SELECT concat_tsvectors(text_search_vector) FROM askbot_post' ||
+        ' WHERE parent_id=' || parent_id || 
+        ' AND post_type=''comment'' AND deleted=false';
+    FOR onerow IN EXECUTE query LOOP
+        RETURN onerow.concat_tsvectors;
+    END LOOP;
+    RETURN to_tsvector('');
+END;
+$$ LANGUAGE plpgsql;
+
+DROP FUNCTION IF EXISTS get_dependent_answers_tsv(question_id integer);
+CREATE OR REPLACE FUNCTION get_dependent_answers_tsv(thread_id integer)
+RETURNS tsvector AS
+$$
+DECLARE
+    query text;
+    onerow record;
+BEGIN
+    query = 'SELECT concat_tsvectors(text_search_vector) ' ||
+       'FROM askbot_post WHERE thread_id = ' || thread_id ||
+       ' AND deleted=false';
+    FOR onerow IN EXECUTE query LOOP
+        RETURN onerow.concat_tsvectors;
+    END LOOP;
+    RETURN to_tsvector('');
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS thread_search_vector_update_trigger on askbot_thread;
+DROP TRIGGER IF EXISTS thread_search_vector_insert_trigger on askbot_thread;
+DROP TRIGGER IF EXISTS post_search_vector_update_trigger on askbot_post;
+
+/* create tsvector columns in the content tables
+ need to isolate these into own transactions, b/c of a weird mix
+ of triggers/update and alter table statements
+*/
+SELECT add_tsvector_column('text_search_vector', 'askbot_thread');
+COMMIT;
+BEGIN;
+SELECT add_tsvector_column('text_search_vector', 'askbot_post');
+COMMIT;
+BEGIN;
+SELECT add_tsvector_column('title_search_vector', 'askbot_thread');
+COMMIT;
+BEGIN;
+
+/* one trigger per table for tsv updates */
+
+/* set up update triggers */
+CREATE OR REPLACE FUNCTION thread_update_trigger() RETURNS trigger AS
+$$
+DECLARE
+    title_tsv tsvector;
+BEGIN
+    title_tsv = get_thread_tsv(new.title, new.tagnames, new.language_code);
+    new.title_search_vector = title_tsv;
+    new.text_search_vector = title_tsv ||
+                             get_thread_question_tsv(new.id) ||
+                             get_dependent_answers_tsv(new.id);
+    RETURN new;
+END;
+$$ LANGUAGE plpgsql;
+CREATE TRIGGER thread_search_vector_update_trigger 
+BEFORE UPDATE ON askbot_thread FOR EACH ROW EXECUTE PROCEDURE thread_update_trigger();
+
+CREATE OR REPLACE FUNCTION thread_insert_trigger() RETURNS trigger AS
+$$
+BEGIN
+    new.text_search_vector = get_thread_tsv(new.title, new.tagnames, new.language_code);
+    RETURN new;
+END;
+$$ LANGUAGE plpgsql;
+CREATE TRIGGER thread_search_vector_insert_trigger
+BEFORE INSERT ON askbot_thread FOR EACH ROW EXECUTE PROCEDURE thread_insert_trigger();
+
+/* post trigger */
+CREATE OR REPLACE FUNCTION post_trigger() RETURNS trigger AS
+$$
+BEGIN
+    IF new.post_type = 'question' THEN
+        new.text_search_vector = get_post_tsv(new.text, 'question', new.language_code) ||
+                                 get_dependent_comments_tsv(new.id);
+    ELSIF new.post_type = 'answer' THEN
+        new.text_search_vector = get_post_tsv(new.text, 'answer', new.language_code) ||
+                                 get_dependent_comments_tsv(new.id);
+    ELSIF new.post_type = 'comment' THEN
+        new.text_search_vector = get_post_tsv(new.text, 'comment', new.language_code);
+    END IF;
+    UPDATE askbot_thread SET id=new.thread_id WHERE id=new.thread_id;
+    return new;
+END;
+$$ LANGUAGE plpgsql;
+CREATE TRIGGER post_search_vector_update_trigger 
+BEFORE INSERT OR UPDATE ON askbot_post FOR EACH ROW EXECUTE PROCEDURE post_trigger();
+
+/* populate tsvectors with data */
+-- post tsvectors
+UPDATE askbot_post set text_search_vector = get_post_tsv(text, post_type, language_code) WHERE post_type IN ('answer', 'comment', 'question');
+UPDATE askbot_post as q SET text_search_vector = text_search_vector ||
+    get_dependent_comments_tsv(q.id) WHERE post_type IN ('question', 'answer');
+
+--thread tsvector
+UPDATE askbot_thread SET text_search_vector = get_thread_tsv(title, tagnames, language_code);
+UPDATE askbot_thread as t SET text_search_vector = text_search_vector ||
+    get_dependent_answers_tsv(t.id) ||
+    get_thread_question_tsv(t.id);
+UPDATE askbot_thread SET title_search_vector = get_thread_tsv(title, tagnames, language_code);
+DROP INDEX IF EXISTS askbot_search_idx;
+CREATE INDEX askbot_search_idx ON askbot_thread USING gin(text_search_vector);