Introduction of SPCsvLoader to load special phrases from a csv file

nominatim/clicmd/special_phrases.py

@@ -2,11 +2,12 @@
     Implementation of the 'special-phrases' command.
 """
 import logging
-from nominatim.errors import UsageError
 from pathlib import Path
-from nominatim.tools import SPWikiLoader
-from nominatim.tools import SPImporter
+from nominatim.errors import UsageError
 from nominatim.db.connection import connect
+from nominatim.tools.special_phrases.sp_importer import SPImporter
+from nominatim.tools.special_phrases.sp_wiki_loader import SPWikiLoader
+from nominatim.tools.special_phrases.sp_csv_loader import SPCsvLoader
 
 LOG = logging.getLogger()
 
@@ -24,23 +25,33 @@ class ImportSpecialPhrases:
         group = parser.add_argument_group('Input arguments')
         group.add_argument('--import-from-wiki', action='store_true',
                            help='Import special phrases from the OSM wiki to the database.')
-        group.add_argument('--csv-file', metavar='FILE',
-                    help='CSV file containing phrases to import.')
+        group.add_argument('--import-from-csv', metavar='FILE',
+                           help='Import special phrases from a CSV file.')
 
     @staticmethod
     def run(args):
-        from ..tokenizer import factory as tokenizer_factory
-
         if args.import_from_wiki:
-            tokenizer = tokenizer_factory.get_tokenizer_for_db(args.config)
-            with connect(args.config.get_libpq_dsn()) as db_connection:
-                SPImporter(
-                    args.config, args.phplib_dir, db_connection, SPWikiLoader(args.config)
-                ).import_phrases(tokenizer)
+            ImportSpecialPhrases.start_import(args, SPWikiLoader(args.config))
 
-        if args.csv_file:
-            if not Path(args.csv_file).is_file():
-                LOG.fatal("CSV file '%s' does not exist.", args.csv_file)
+        if args.import_from_csv:
+            if not Path(args.import_from_csv).is_file():
+                LOG.fatal("CSV file '%s' does not exist.", args.import_from_csv)
                 raise UsageError('Cannot access file.')
 
+            ImportSpecialPhrases.start_import(args, SPCsvLoader(args.import_from_csv))
+
         return 0
+
+    @staticmethod
+    def start_import(args, loader):
+        """
+            Create the SPImporter object containing the right
+            SPLoader and then start the import of special phrases.
+        """
+        from ..tokenizer import factory as tokenizer_factory
+
+        tokenizer = tokenizer_factory.get_tokenizer_for_db(args.config)
+        with connect(args.config.get_libpq_dsn()) as db_connection:
+            SPImporter(
+                args.config, args.phplib_dir, db_connection, loader
+            ).import_phrases(tokenizer)

nominatim/tools/__init__.py

@@ -2,7 +2,3 @@
 Module with functions for importing, updating Nominatim databases
 as well as general maintenance helpers.
 """
-
-from nominatim.tools.special_phrases.sp_importer import SPImporter
-from nominatim.tools.special_phrases.sp_wiki_loader import SPWikiLoader
-from nominatim.tools.special_phrases.special_phrase import SpecialPhrase

nominatim/tools/special_phrases/sp_csv_loader.py

@@ -0,0 +1,54 @@
+"""
+    Module containing the SPCsvLoader class.
+
+    The class allows to load phrases from a csv file.
+"""
+import csv
+import os
+from nominatim.tools.special_phrases.special_phrase import SpecialPhrase
+from nominatim.tools.special_phrases.sp_loader import SPLoader
+from nominatim.errors import UsageError
+
+class SPCsvLoader(SPLoader):
+    """
+        Base class for special phrases loaders.
+        Handle the loading of special phrases from external sources.
+    """
+    def __init__(self, csv_path):
+        super().__init__()
+        self.csv_path = csv_path
+        self.has_been_read = False
+
+    def __next__(self):
+        if self.has_been_read:
+            raise StopIteration()
+
+        self.has_been_read = True
+        SPCsvLoader.check_csv_validity(self.csv_path)
+        return SPCsvLoader.parse_csv(self.csv_path)
+
+    @staticmethod
+    def parse_csv(csv_path):
+        """
+            Open and parse the given csv file.
+            Create the corresponding SpecialPhrases.
+        """
+        phrases = set()
+
+        with open(csv_path) as file:
+            reader = csv.DictReader(file, delimiter=',')
+            for row in reader:
+                phrases.add(
+                    SpecialPhrase(row['phrase'], row['class'], row['type'], row['operator'])
+                )
+        return phrases
+
+    @staticmethod
+    def check_csv_validity(csv_path):
+        """
+            Check that the csv file has the right extension.
+        """
+        _, extension = os.path.splitext(csv_path)
+
+        if extension != '.csv':
+            raise UsageError('The file {} is not a csv file.'.format(csv_path))

nominatim/tools/special_phrases/sp_wiki_loader.py

@@ -1,8 +1,8 @@
 """
     Module containing the SPWikiLoader class.
 """
-import logging
 import re
+import logging
 from nominatim.tools.special_phrases.special_phrase import SpecialPhrase
 from nominatim.tools.special_phrases.sp_loader import SPLoader
 from nominatim.tools.exec_utils import get_url