Throw invalid column count errors where the insert statement is executed

Psycopg 3 throws a generic ProgramimgError, so core.py has trouble
reporting the problem.  Perhaps this can be solved by creating a
generic PreparedStmt class at the core level, but this works for
the moment.

diff --git a/src/pgwui_upload_core/views/upload.py b/src/pgwui_upload_core/views/upload.py
index ba6b7a5f6117fcf3a223111f54fd1aae3b8c7871..6184035fdbb2617d815c01146bbf5d9a78d0b36e 100644 (file)
--- a/src/pgwui_upload_core/views/upload.py
+++ b/src/pgwui_upload_core/views/upload.py
@@ -29,6 +29,8 @@ import logging
 import markupsafe
 import psycopg.errors
 
+from html import escape as html_escape
+
 from pgwui_core.core import (
     UploadNullFileInitialPost,
     TabularFileUploadHandler,
@@ -124,7 +126,7 @@ class BaseTableUploadHandler(TabularFileUploadHandler):
         self.write_double_key(response)
         return response
 
-    def _execute(self, stmt, tupl):
+    def execute(self, stmt, tupl):
         '''Execute a statement and express encoding errors
         '''
         try:
@@ -149,7 +151,7 @@ class BaseTableUploadHandler(TabularFileUploadHandler):
         if not resolvable.
         '''
         try:
-            self._execute(
+            self.execute(
                 ('SELECT nspname, relname'
                  '  FROM pg_class'
                  '       JOIN pg_namespace'
@@ -212,7 +214,7 @@ class BaseTableUploadHandler(TabularFileUploadHandler):
                # tables.is_insertable_into does not reflect whether
                # there's an insert trigger on the table.
                "             OR tables.table_type = 'VIEW')")
-        self._execute(sql, (table, schema))
+        self.execute(sql, (table, schema))
         return self.cur.fetchone() is not None
 
     def quote_columns(self, settings):
@@ -281,7 +283,33 @@ class BaseTableUploadHandler(TabularFileUploadHandler):
 
     def build_insert_stmt(
             self, data, qualified_table, quotecols, column_quoter):
-        schema, table = self.validate_table(qualified_table)
+        insert_stmt = InsertStmt()
+        insert_stmt.build_insert_stmt(
+            self, data, qualified_table, quotecols, column_quoter)
+        return insert_stmt
+
+    def factory(self, ue):
+        '''Make a db loader function from an UploadEngine.
+
+        Input:
+
+        Side Effects:
+          Assigns: self.ue, self.cur
+          And, lots of changes to the db
+        '''
+        self.ue = ue
+        self.cur = ue.cur
+
+
+@attrs.define
+class InsertStmt:
+    stmt = attrs.field(default=None)
+    cols = attrs.field(default=None)
+
+    def build_insert_stmt(
+            self, tuh, data, qualified_table, quotecols, column_quoter):
+        '''tuh: A TableUploadHandler'''
+        schema, table = tuh.validate_table(qualified_table)
 
         column_sql = ('SELECT 1 FROM information_schema.columns'
                       '  WHERE columns.table_name = %s'
@@ -291,37 +319,26 @@ class BaseTableUploadHandler(TabularFileUploadHandler):
         else:
             column_sql += '    AND columns.column_name = lower(%s::name)'
 
-        insert_stmt = f'INSERT INTO {self.quotetable(schema, table)} ('
+        self.stmt = f'INSERT INTO {tuh.quotetable(schema, table)} ('
         value_string = ''
         col_sep = ''
         bad_cols = []
         for col_name in data.headers.tuples:
             # Check that colum name exists
-            self._execute(column_sql, (table, schema, col_name))
-            if self.cur.fetchone() is None:
+            tuh.execute(column_sql, (table, schema, col_name))
+            if tuh.cur.fetchone() is None:
                 bad_cols.append(col_name)
             else:
                 # Add column to sql statement
-                insert_stmt += col_sep + column_quoter(col_name)
+                self.stmt += col_sep + column_quoter(col_name)
                 value_string += col_sep + '%s'
                 col_sep = ', '
 
         if bad_cols:
             self.report_bad_cols(qualified_table, bad_cols, quotecols)
 
-        return insert_stmt + ') VALUES({0})'.format(value_string)
-
-    def factory(self, ue):
-        '''Make a db loader function from an UploadEngine.
-
-        Input:
-
-        Side Effects:
-          Assigns: self.ue, self.cur
-          And, lots of changes to the db
-        '''
-        self.ue = ue
-        self.cur = ue.cur
+        self.stmt += ') VALUES({0})'.format(value_string)
+        self.cols = len(data.headers.tuples)
 
 
 def set_upload_response(component, request, response):
@@ -335,3 +352,28 @@ def set_upload_response(component, request, response):
 
     response.setdefault('pgwui', dict())
     response['pgwui']['upload_settings'] = upload_settings
+
+
+def match_insert_to_dataline(udl, insert_stmt, source_file=None):
+    '''Make sure the UploadDataLine has the number of values expected
+    by the insert statement
+    '''
+    data_cols = len(udl.tuples)
+    if data_cols != insert_stmt.cols:
+        descr = ('The number of data columns does not match the'
+                 " number of headings given in the file's first line")
+
+        source_detail = ''
+        if source_file is not None:
+            source_detail = f'File: ({html_escape(source_file)}); '
+        detail = (f'{source_detail}'
+                  f'Expected number of columns: {data_cols}')
+
+        if data_cols > insert_stmt.cols:
+            raise core_ex.TooManyColsError(
+                udl.lineno, 'Too many data columns', descr=descr,
+                detail=detail, data=udl.raw)
+        else:
+            raise core_ex.TooFewColsError(
+                udl.lineno, 'Too few data columns', descr=descr,
+                detail=detail, data=udl.raw)