misc: allow prefilling file fields with a dictionary (#25385)

tests/form_pages/test_file_field.py

@@ -11,6 +11,7 @@ from wcs.blocks import BlockDef
 from wcs.categories import Category
 from wcs.formdef import FormDef
 from wcs.qommon.errors import ConnectionError
+from wcs.wscalls import NamedWsCall
 
 from ..utilities import clean_temporary_pub, create_temporary_pub, get_app, login
 from .test_all import create_user
@@ -491,6 +492,40 @@ def test_form_file_field_prefill(pub):
     assert formdata.data['0'].get_content().startswith(b'\x89PNG')
 
 
+@responses.activate
+def test_form_file_field_dict_prefill(pub):
+    NamedWsCall.wipe()
+    wscall = NamedWsCall()
+    wscall.name = 'Hello'
+    wscall.request = {'url': 'http://example.net'}
+    wscall.store()
+
+    FormDef.wipe()
+    formdef = FormDef()
+    formdef.name = 'test'
+    formdef.fields = [
+        fields.FileField(
+            id='0',
+            label='file',
+            prefill={'type': 'string', 'value': '{{ webservice.hello }}'},
+        )
+    ]
+    formdef.store()
+
+    responses.get(
+        'http://example.net',
+        json={'b64_content': 'aGVsbG8K', 'filename': 'hello.txt', 'content_type': 'text/plain'},
+    )
+    resp = get_app(pub).get('/test/')
+    assert resp.form['f0$token']
+    assert resp.click('hello.txt').content_type == 'text/plain'
+    resp = resp.form.submit('submit')  # -> validation
+    resp = resp.form.submit('submit')  # -> submit
+    formdata = formdef.data_class().select()[0]
+    assert formdata.data['0'].base_filename == 'hello.txt'
+    assert formdata.data['0'].get_content() == b'hello\n'
+
+
 SVG_CONTENT = b'''<?xml version="1.0" encoding="utf-8"?>
 <svg version="1.1" id="Calque_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
 viewBox="0 0 63.72 64.25" style="enable-background:new 0 0 63.72 64.25;" xml:space="preserve"> <g> </g> </svg>'''

wcs/qommon/form.py

@@ -924,6 +924,13 @@ class FileWithPreviewWidget(CompositeWidget):
         return False
 
     def set_value(self, value):
+        if isinstance(value, dict):
+            from wcs.fields.file import FileField
+
+            try:
+                value = FileField.convert_value_from_anything(value)
+            except ValueError:
+                value = None
         try:
             self.value = value
             if self.value and self.get_value_from_token: