X-Git-Url: https://git.jsancho.org/?p=datasette-pytables.git;a=blobdiff_plain;f=datasette_pytables%2F__init__.py;h=93f9b89cfa0577b9d4b10215cec6b191c595c3d3;hp=93be0f9a1206208f3667633526baca08b28ae335;hb=8d58881ab27b2acfc1f08f4108f8b4ac443b0204;hpb=25d0571fb4a85291df0f7cea4f1424588a7961fc

diff --git a/datasette_pytables/__init__.py b/datasette_pytables/__init__.py
index 93be0f9..93f9b89 100644
--- a/datasette_pytables/__init__.py
+++ b/datasette_pytables/__init__.py
@@ -1,6 +1,6 @@
+from moz_sql_parser import parse
+import re
 import tables
-import sqlparse
-from collections import OrderedDict
 
 _connector_type = 'pytables'
 
@@ -11,7 +11,7 @@ def inspect(path):
     h5file = tables.open_file(path)
 
     for table in filter(lambda node: not(isinstance(node, tables.group.Group)), h5file):
-        colnames = []
+        colnames = ['value']
         if isinstance(table, tables.table.Table):
             colnames = table.colnames
 
@@ -19,7 +19,7 @@ def inspect(path):
             'name': table._v_pathname,
             'columns': colnames,
             'primary_keys': [],
-            'count': table.nrows,
+            'count': int(table.nrows),
             'label_column': None,
             'hidden': False,
             'fts_table': None,
@@ -29,69 +29,252 @@ def inspect(path):
     h5file.close()
     return h5tables, views, _connector_type
 
-def _parse_sql(sql):
-    parsed = sqlparse.parse(sql)
-    stmt = parsed[0]
-    parsed_sql = {}
-    current_keyword = ""
-    for token in stmt.tokens:
-        if token.is_keyword:
-            if current_keyword in parsed_sql and parsed_sql[current_keyword] == '':
-                # Check composed keywords like 'order by'
-                del parsed_sql[current_keyword]
-                current_keyword += " " + str(token)
-            else:
-                current_keyword = str(token)
-            parsed_sql[current_keyword] = ""
-        else:
-            if not token.is_whitespace:
-                parsed_sql[current_keyword] += str(token)
-    return parsed_sql
+def _parse_sql(sql, params):
+    # Table name
+    sql = re.sub('(?i)from \[(.*)]', 'from "\g<1>"', sql)
+    # Params
+    for param in params:
+        sql = sql.replace(":" + param, param)
+
+    try:
+        parsed = parse(sql)
+    except:
+        # Propably it's a PyTables expression
+        for token in ['group by', 'order by', 'limit', '']:
+            res = re.search('(?i)where (.*)' + token, sql)
+            if res:
+                modified_sql = re.sub('(?i)where (.*)(' + token + ')', '\g<2>', sql)
+                parsed = parse(modified_sql)
+                parsed['where'] = res.group(1).strip()
+                break
+
+    # Always a list of fields
+    if type(parsed['select']) is not list:
+        parsed['select'] = [parsed['select']]
+
+    return parsed
+
+_operators = {
+    'eq': '==',
+    'neq': '!=',
+    'gt': '>',
+    'gte': '>=',
+    'lt': '<',
+    'lte': '<=',
+    'and': '&',
+    'or': '|',
+}
 
 class Connection:
     def __init__(self, path):
         self.path = path
         self.h5file = tables.open_file(path)
 
-    def execute(self, sql, params=None, truncate=False):
+    def execute(self, sql, params=None, truncate=False, page_size=None, max_returned_rows=None):
+        if params is None:
+            params = {}
         rows = []
         truncated = False
         description = []
 
-        parsed_sql = _parse_sql(sql)
-        table = self.h5file.get_node(parsed_sql['from'][1:-1])
+        parsed_sql = _parse_sql(sql, params)
+
+        if parsed_sql['from'] == 'sqlite_master':
+            rows = self._execute_datasette_query(sql, params)
+            description = (('value',))
+            return rows, truncated, description
+
+        table = self.h5file.get_node(parsed_sql['from'])
         table_rows = []
-        fields = parsed_sql['select'].split(',')
+        fields = parsed_sql['select']
+        colnames = ['value']
+        if type(table) is tables.table.Table:
+            colnames = table.colnames
+
+        query = ''
+        start = 0
+        end = table.nrows
 
         # Use 'where' statement or get all the rows
+        def _cast_param(field, pname):
+            # Cast value to the column type
+            coltype = table.dtype.name
+            if type(table) is tables.table.Table:
+                coltype = table.coltypes[field]
+            fcast = None
+            if coltype == 'string':
+                fcast = str
+            elif coltype.startswith('int'):
+                fcast = int
+            elif coltype.startswith('float'):
+                fcast = float
+            if fcast:
+                params[pname] = fcast(params[pname])
+
+        def _translate_where(where):
+            # Translate SQL to PyTables expression
+            nonlocal start, end
+            expr = ''
+            operator = list(where)[0]
+
+            if operator in ['and', 'or']:
+                subexpr = [_translate_where(e) for e in where[operator]]
+                subexpr = filter(lambda e: e, subexpr)
+                subexpr = ["({})".format(e) for e in subexpr]
+                expr = " {} ".format(_operators[operator]).join(subexpr)
+            elif operator == 'exists':
+                pass
+            elif where == {'eq': ['rowid', 'p0']}:
+                start = int(params['p0'])
+                end = start + 1
+            elif where == {'gt': ['rowid', 'p0']}:
+                start = int(params['p0']) + 1
+            else:
+                left, right = where[operator]
+                if left in params:
+                    _cast_param(right, left)
+                elif right in params:
+                    _cast_param(left, right)
+
+                expr = "{left} {operator} {right}".format(left=left, operator=_operators.get(operator, operator), right=right)
+
+            return expr
+
         if 'where' in parsed_sql:
-            pass
+            if type(parsed_sql['where']) is dict:
+                query = _translate_where(parsed_sql['where'])
+            else:
+                query = parsed_sql['where']
+
+        # Limit number of rows
+        limit = None
+        if 'limit' in parsed_sql:
+            limit = int(parsed_sql['limit'])
+
+        # Truncate if needed
+        if page_size and max_returned_rows and truncate:
+            if max_returned_rows == page_size:
+                max_returned_rows += 1
+
+        # Execute query
+        if query:
+            table_rows = table.where(query, params, start, end)
         else:
-            table_rows = table.iterrows()
+            table_rows = table.iterrows(start, end)
+
+        # Prepare rows
+        def normalize_field_value(value):
+            if type(value) is bytes:
+                return value.decode('utf-8')
+            elif not type(value) in (int, float, complex):
+                return str(value)
+            else:
+                return value
+
+        def make_get_rowid():
+            if type(table) is tables.table.Table:
+                def get_rowid(row):
+                    return int(row.nrow)
+            else:
+                rowid = start - 1
+                def get_rowid(row):
+                    nonlocal rowid
+                    rowid += 1
+                    return rowid
+            return get_rowid
+
+        def make_get_row_value():
+            if type(table) is tables.table.Table:
+                def get_row_value(row, field):
+                    return row[field]
+            else:
+                def get_row_value(row, field):
+                    return row
+            return get_row_value
 
-        if len(fields) == 1 and fields[0] == 'count(*)':
-            rows.append(Row({'count(*)': table.nrows}))
+        if len(fields) == 1 and type(fields[0]['value']) is dict and \
+           fields[0]['value'].get('count') == '*':
+            rows.append(Row({'count(*)': int(table.nrows)}))
         else:
+            get_rowid = make_get_rowid()
+            get_row_value = make_get_row_value()
+            count = 0
             for table_row in table_rows:
+                count += 1
+                if limit and count > limit:
+                    break
+                if truncate and max_returned_rows and count > max_returned_rows:
+                    truncated = True
+                    break
                 row = Row()
                 for field in fields:
-                    if field == 'rowid':
-                        row[field] = table_row.nrow
-                    elif field == '*':
-                        for col in table.colnames:
-                            row[col] = table_row[col]
+                    field_name = field['value']
+                    if type(field_name) is dict and 'distinct' in field_name:
+                        field_name = field_name['distinct']
+                    if field_name == 'rowid':
+                        row['rowid'] = get_rowid(table_row)
+                    elif field_name == '*':
+                        for col in colnames:
+                            row[col] = normalize_field_value(get_row_value(table_row, col))
                     else:
-                        row[field] = table_row[field]
+                        row[field_name] = normalize_field_value(get_row_value(table_row, field_name))
                 rows.append(row)
 
-        description = ((col,) for col in table.colnames)
+        # Prepare query description
+        for field in [f['value'] for f in fields]:
+            if field == '*':
+                for col in colnames:
+                    description.append((col,))
+            else:
+                description.append((field,))
 
-        if truncate:
-            return rows, truncated, description
+        # Return the rows
+        return rows, truncated, tuple(description)
+
+    def _execute_datasette_query(self, sql, params):
+        "Datasette special queries for getting tables info"
+        if sql == "SELECT count(*) from sqlite_master WHERE type = 'view' and name=:n":
+            row = Row()
+            row['count(*)'] = 0
+            return [row]
+        elif sql == 'select sql from sqlite_master where name = :n and type="table"':
+            try:
+                table = self.h5file.get_node(params['n'])
+                colnames = ['value']
+                if type(table) is tables.table.Table:
+                    colnames = table.colnames
+                row = Row()
+                row['sql'] = 'CREATE TABLE {} ({})'.format(params['n'], ", ".join(colnames))
+                return [row]
+            except:
+                return []
+        else:
+            raise Exception("SQLite queries cannot be executed with this connector")
+
+
+class Row(list):
+    def __init__(self, values=None):
+        self.labels = []
+        self.values = []
+        if values:
+            for idx in values:
+                self.__setitem__(idx, values[idx])
+
+    def __setitem__(self, idx, value):
+        if type(idx) is str:
+            if idx in self.labels:
+                self.values[self.labels.index(idx)] = value
+            else:
+                self.labels.append(idx)
+                self.values.append(value)
+        else:
+            self.values[idx] = value
+
+    def __getitem__(self, idx):
+        if type(idx) is str:
+            return self.values[self.labels.index(idx)]
         else:
-            return rows
+            return self.values[idx]
 
-class Row(OrderedDict):
-    def __getitem__(self, label):
-        if type(label) is int:
-            return super(OrderedDict, self).__getitem__(list(self.keys())[label])
+    def __iter__(self):
+        return self.values.__iter__()