本地实现records和tablib

common/tablib/format.py

@@ -0,0 +1,120 @@
+""" Tablib - JSON Support
+"""
+import decimal
+import json
+from uuid import UUID
+
+from . import tablib
+
+
+def serialize_objects_handler(obj):
+    if isinstance(obj, (decimal.Decimal, UUID)):
+        return str(obj)
+    elif hasattr(obj, 'isoformat'):
+        return obj.isoformat()
+    else:
+        return obj
+
+
+class JSONFormat:
+    title = 'json'
+    extensions = ('json',)
+
+    @classmethod
+    def export_set(cls, dataset):
+        """Returns JSON representation of Dataset."""
+        return json.dumps(dataset.dict, default=serialize_objects_handler)
+
+    @classmethod
+    def export_book(cls, databook):
+        """Returns JSON representation of Databook."""
+        return json.dumps(databook._package(), default=serialize_objects_handler)
+
+    @classmethod
+    def import_set(cls, dset, in_stream):
+        """Returns dataset from JSON stream."""
+
+        dset.wipe()
+        dset.dict = json.load(in_stream)
+
+    @classmethod
+    def import_book(cls, dbook, in_stream):
+        """Returns databook from JSON stream."""
+
+        dbook.wipe()
+        for sheet in json.load(in_stream):
+            data = tablib.Dataset()
+            data.title = sheet['title']
+            data.dict = sheet['data']
+            dbook.add_sheet(data)
+
+    @classmethod
+    def detect(cls, stream):
+        """Returns True if given stream is valid JSON."""
+        try:
+            json.load(stream)
+            return True
+        except (TypeError, ValueError):
+            return False
+
+
+""" Tablib - *SV Support.
+"""
+
+import csv
+from io import StringIO
+
+
+class CSVFormat:
+    title = 'csv'
+    extensions = ('csv',)
+
+    DEFAULT_DELIMITER = ','
+
+    @classmethod
+    def export_stream_set(cls, dataset, **kwargs):
+        """Returns CSV representation of Dataset as file-like."""
+        stream = StringIO()
+
+        kwargs.setdefault('delimiter', cls.DEFAULT_DELIMITER)
+
+        _csv = csv.writer(stream, **kwargs)
+
+        for row in dataset._package(dicts=False):
+            _csv.writerow(row)
+
+        stream.seek(0)
+        return stream
+
+    @classmethod
+    def export_set(cls, dataset, **kwargs):
+        """Returns CSV representation of Dataset."""
+        stream = cls.export_stream_set(dataset, **kwargs)
+        return stream.getvalue()
+
+    @classmethod
+    def import_set(cls, dset, in_stream, headers=True, **kwargs):
+        """Returns dataset from CSV stream."""
+
+        dset.wipe()
+
+        kwargs.setdefault('delimiter', cls.DEFAULT_DELIMITER)
+
+        rows = csv.reader(in_stream, **kwargs)
+        for i, row in enumerate(rows):
+
+            if (i == 0) and (headers):
+                dset.headers = row
+            elif row:
+                if i > 0 and len(row) < dset.width:
+                    row += [''] * (dset.width - len(row))
+                dset.append(row)
+
+    @classmethod
+    def detect(cls, stream, delimiter=None):
+        """Returns True if given stream is valid CSV."""
+        try:
+            csv.Sniffer().sniff(stream.read(1024), delimiters=delimiter or cls.DEFAULT_DELIMITER)
+            return True
+        except Exception:
+            return False