]> git.jsancho.org Git - datasette-pytables.git/blobdiff - datasette_pytables/__init__.py
Getting ready for 2.0.0 final
[datasette-pytables.git] / datasette_pytables / __init__.py
index b857ee179bb744a1e64dca0fa09834fb8ee35b53..4c1cc0f9837aff45375c1f6c1654b8e71d359094 100644 (file)
-from collections import OrderedDict
-import sqlparse
 import tables
+import datasette_connectors as dc
+from .utils import parse_sql
 
-_connector_type = 'pytables'
 
-def inspect(path):
-    "Open file and return tables info"
-    h5tables = {}
-    views = []
-    h5file = tables.open_file(path)
+class PyTablesConnection(dc.Connection):
+    def __init__(self, path, connector):
+        super().__init__(path, connector)
+        self.h5file = tables.open_file(path)
+
+
+class PyTablesConnector(dc.Connector):
+    connector_type = 'pytables'
+    connection_class = PyTablesConnection
+
+    operators = {
+        'eq': '==',
+        'neq': '!=',
+        'gt': '>',
+        'gte': '>=',
+        'lt': '<',
+        'lte': '<=',
+        'and': '&',
+        'or': '|',
+        'binary_and': '&',
+        'binary_or': '|',
+    }
+
+    def _serialize_table_name(self, table_name):
+        return table_name.replace('/', '%')
+
+    def _deserialize_table_name(self, table_name):
+        return table_name.replace('%', '/')
+
+    def table_names(self):
+        return [
+            self._serialize_table_name(node._v_pathname)
+            for node in self.conn.h5file
+            if not(isinstance(node, tables.group.Group))
+        ]
+
+    def table_count(self, table_name):
+        table = self.conn.h5file.get_node(self._deserialize_table_name(table_name))
+        return int(table.nrows)
 
-    for table in filter(lambda node: not(isinstance(node, tables.group.Group)), h5file):
-        colnames = []
+    def table_info(self, table_name):
+        table = self.conn.h5file.get_node(self._deserialize_table_name(table_name))
+        columns = [
+            {
+                'name': 'value',
+                'type': table.dtype.name,
+            }
+        ]
         if isinstance(table, tables.table.Table):
-            colnames = table.colnames
+            columns = [
+                {
+                    'name': colname,
+                    'type': table.coltypes[colname],
+                }
+                for colname in table.colnames
+            ]
 
-        h5tables[table._v_pathname] = {
-            'name': table._v_pathname,
-            'columns': colnames,
-            'primary_keys': [],
-            'count': int(table.nrows),
-            'label_column': None,
-            'hidden': False,
-            'fts_table': None,
-            'foreign_keys': {'incoming': [], 'outgoing': []},
-        }
-
-    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] = ""
-        elif type(token) is sqlparse.sql.Where:
-            parsed_sql['where'] = token
-        else:
-            if not token.is_whitespace:
-                parsed_sql[current_keyword] += str(token)
-    return parsed_sql
-
-_operators = {
-    '=': '==',
-}
-
-def _translate_condition(table, condition, params):
-    field = condition.left.get_real_name()
-
-    operator = list(filter(lambda t: t.ttype == sqlparse.tokens.Comparison, condition.tokens))[0]
-    if operator.value in _operators:
-        operator = _operators[operator.value]
-    else:
-        operator = operator.value
-
-    value = condition.right.value
-    if value.startswith(':'):
-        # Value is a parameters
-        value = value[1:]
-        if value in params:
-            # Cast value to the column type
-            coltype = table.coltypes[field]
-            if coltype == 'string':
-                params[value] = str(params[value])
-            elif coltype.startswith('int'):
-                params[value] = int(params[value])
-            elif coltype.startswith('float'):
-                params[value] = float(params[value])
+        return [
+            {
+                'cid': cid,
+                'name': column['name'],
+                'type': column['type'],
+                'notnull': True,
+                'default_value': None,
+                'is_pk': False,
+            }
+            for cid, column in enumerate(columns)
+        ]
 
-    translated = "{left} {operator} {right}".format(left=field, operator=operator, right=value)
-    return translated, params
+    def hidden_table_names(self):
+        return []
 
-class Connection:
-    def __init__(self, path):
-        self.path = path
-        self.h5file = tables.open_file(path)
+    def detect_spatialite(self):
+        return False
+
+    def view_names(self):
+        return []
+
+    def detect_fts(self, table_name):
+        return False
+
+    def foreign_keys(self, table_name):
+        return []
+
+    def table_exists(self, table_name):
+        try:
+            self.conn.h5file.get_node(self._deserialize_table_name(table_name))
+            return True
+        except:
+            return False
+
+    def table_definition(self, table_type, table_name):
+        table_name = self._deserialize_table_name(table_name)
+        table = self.conn.h5file.get_node(table_name)
+        colnames = ['value']
+        if isinstance(table, tables.table.Table):
+            colnames = table.colnames
+
+        return 'CREATE TABLE {} ({})'.format(
+            table_name,
+            ', '.join(colnames),
+        )
 
-    def execute(self, sql, params=None, truncate=False):
-        if params is None:
-            params = {}
-        rows = []
+    def indices_definition(self, table_name):
+        return []
+
+    def execute(
+        self,
+        sql,
+        params=None,
+        truncate=False,
+        custom_time_limit=None,
+        page_size=None,
+        log_sql_errors=True,
+    ):
+        results = []
         truncated = False
-        description = []
+        description = ()
+
+        # Some Datasette queries uses glob operand, not supported by Pytables
+        if ' glob ' in sql:
+            return results, truncated, description
 
-        parsed_sql = _parse_sql(sql)
-        table = self.h5file.get_node(parsed_sql['from'][1:-1])
+        parsed_sql = parse_sql(sql, params)
+
+        while isinstance(parsed_sql['from'], dict):
+            # Pytables does not support subqueries
+            parsed_sql['from'] = parsed_sql['from']['value']['from']
+
+        table = self.conn.h5file.get_node(self._deserialize_table_name(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
 
+        def _get_field_type(field):
+            coltype = table.dtype.name
+            if type(table) is tables.table.Table:
+                coltype = table.coltypes[field]
+            return coltype
+
         # Use 'where' statement or get all the rows
+        def _cast_param(field, pname):
+            # Cast value to the column type
+            coltype = _get_field_type(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(self.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 isinstance(left, dict):
+                    left = "(" + _translate_where(left) + ")"
+                elif left in params:
+                    _cast_param(right, left)
+
+                if isinstance(right, dict):
+                    right = "(" + _translate_where(right) + ")"
+                elif right in params:
+                    _cast_param(left, right)
+
+                expr = "{left} {operator} {right}".format(
+                    left=left,
+                    operator=self.operators.get(operator, operator),
+                    right=right,
+                )
+
+            return expr
+
         if 'where' in parsed_sql:
-            try:
-                conditions = []
-                for condition in parsed_sql['where'].get_sublists():
-                    if str(condition) == '"rowid"=:p0':
-                        start = int(params['p0'])
-                        end = start + 1
-                    else:
-                        translated, params = _translate_condition(table, condition, params)
-                        conditions.append(translated)
-                if conditions:
-                    query = ') & ('.join(conditions)
-                    query = '(' + query + ')'
-            except:
-                # Probably it's a PyTables query
-                query = str(parsed_sql['where'])[6:]    # without where keyword
+            if type(parsed_sql['where']) is dict:
+                query = _translate_where(parsed_sql['where'])
+            else:
+                query = parsed_sql['where']
+
+        # Sort by column
+        orderby = ''
+        if 'orderby' in parsed_sql:
+            orderby = parsed_sql['orderby']
+            if type(orderby) is list:
+                orderby = orderby[0]
+            orderby = orderby['value']
+            if orderby == 'rowid':
+                orderby = ''
 
         # Limit number of rows
+        limit = None
         if 'limit' in parsed_sql:
-            max_rows = int(parsed_sql['limit'])
-            if end - start > max_rows:
-                end = start + max_rows
+            limit = int(parsed_sql['limit'])
+
+        # Offset
+        offset = None
+        if 'offset' in parsed_sql:
+            offset = int(parsed_sql['offset'])
+
+        # 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)
+        elif orderby:
+            table_rows = table.itersorted(orderby, start=start, stop=end)
         else:
             table_rows = table.iterrows(start, end)
 
         # Prepare rows
-        if len(fields) == 1 and fields[0] == 'count(*)':
-            rows.append(Row({fields[0]: int(table.nrows)}))
-        else:
-            for table_row in table_rows:
-                row = Row()
-                for field in fields:
-                    if field == 'rowid':
-                        row[field] = int(table_row.nrow)
-                    elif field == '*':
-                        for col in table.colnames:
-                            value = table_row[col]
-                            if type(value) is bytes:
-                                value = value.decode('utf-8')
-                            row[col] = value
+        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
+
+        # Get results
+        get_rowid = make_get_rowid()
+        get_row_value = make_get_row_value()
+        if offset:
+            table_rows = table_rows[offset:]
+        count = 0
+        for table_row in table_rows:
+            count += 1
+            if limit is not None and count > limit:
+                break
+            if truncate and max_returned_rows and count > max_returned_rows:
+                truncated = True
+                break
+            row = {}
+            for field in fields:
+                field_name = field
+                if isinstance(field, dict):
+                    field_name = field['value']
+                if isinstance(field_name, 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))
+                elif isinstance(field_name, dict):
+                    if field_name.get('count') == '*':
+                        row['count(*)'] = int(table.nrows)
+                    elif field_name.get('json_type'):
+                        field_name = field_name.get('json_type')
+                        row['json_type(' + field_name + ')'] = _get_field_type(field_name)
                     else:
-                        row[field] = table_row[field]
-                rows.append(row)
+                        raise Exception("Function not recognized")
+                else:
+                    row[field_name] = normalize_field_value(get_row_value(table_row, field_name))
+            results.append(row)
 
         # Prepare query description
-        for field in fields:
+        for field in [f['value'] if isinstance(f, dict) else f for f in fields]:
             if field == '*':
-                for col in table.colnames:
-                    description.append((col,))
+                for col in colnames:
+                    description += ((col,),)
             else:
-                description.append((field,))
-
-        # Return the rows
-        if truncate:
-            return rows, truncated, tuple(description)
-        else:
-            return rows
-
-class Row(OrderedDict):
-    def __getitem__(self, label):
-        if type(label) is int:
-            return super(OrderedDict, self).__getitem__(list(self.keys())[label])
-        else:
-            return super(OrderedDict, self).__getitem__(label)
+                description += ((field,),)
 
-    def __iter__(self):
-        return self.values().__iter__()
+        return results, truncated, description