mycampusscript.py: semi-complete function upload_attachment()

mycampusscript.py

 import collections.abc
 import datetime as dt
+import mimetypes
+import os.path
 import random
 import re
 import sys
 import typing as tg
+import urllib.parse
 
 import bs4
 import yaml
@@ -129,7 +132,8 @@ def main(scriptname: str, cmdname: str, configfile: str):
                                                    dynamic=get_gradebook_categories)
     send_grades_to_gradebook_category: int = find_value_or_help(config, 'send_grades_to_gradebook_category')
     released_grade_notification_email: bool = find_value_or_help(config, 'released_grade_notification_email')
-    upload_attachments(config, attachments)
+    for attachment in attachments:
+        upload_attachment(config, attachment)
 
 
 def find_value_or_help(config: StrAnyDict, key: str, dynamic: ReplacementsFunc = None) -> tg.Any:
@@ -235,7 +239,7 @@ def obtain_tokens(config: StrAnyDict):
     config[RBCS_TOKEN_CONFIGENTRY_NAME] = rbcstoken_input_elem['value']
 
 
-def upload_attachments(config: StrAnyDict, attachments: list[str]):
+def upload_attachment(config: StrAnyDict, filepath: str):
     """
     Make POST request with multipart/formdata body, many headers, and the following format of URL:
     POST /portal/site/<site-id>/tool/1f8f054a-4e58-4965-8d32-141b236e0023/sakai.filepicker.helper?special=upload&sakai_csrf_token=<hexstring>&sakai_action=doAttachupload
@@ -249,7 +253,39 @@ def upload_attachments(config: StrAnyDict, attachments: list[str]):
     # See "POST Multiple Multipart-Encoded Files" in https://requests.readthedocs.io/en/latest/user/advanced/
     # We have so far failed to obtain the HTML of the form to be posted, which we need to find the
     # name of the attachment file form element.
-    
+    # in c:/temp/a.json:
+    # Request 164 ist der POST-Request, den wir analog nachbilden müssen.
+    # Das JSON ist dafür unpraktisch, weil der ganze multipart-Rumpf nur als Text dasteht.
+    # In der Word-Datei findet sich die aufgeschlüsselte Form, die der Browser dafür anzeigt.
+    # Erzeugung eines solchen Requests, siehe https://stackoverflow.com/a/12385661
+    filename = os.path.basename(filepath)
+    content_type, encoding = mimetypes.guess_type(filename)
+    multipart_body = dict(
+        source='0',
+        collectionId=f'/group/{site_id(config["site_url"])}',
+        sakai_action='',
+        navRoot='',
+        criteria='title',
+        rt_action='',
+        selectedItemId='',
+        upload=(filename, slurp(filepath), content_type),
+        url='',
+        sakai_csrf_token=config[CSRF_TOKEN_CONFIGENTRY_NAME]
+    )
+    multipart_body['from'] = 'list'  # separate because 'from' is a keyword
+    requests.post(...)
+
+
+def site_id(site_url: str) -> str:
+    """From e.g. https://qmycampus.imp.fu-berlin.de/portal/site/724a527a-db9d, retrieve 724a527a-db9d"""
+    path = urllib.parse.urlparse(site_url).path
+    the_id = os.path.basename(path)
+    return the_id
+
+
+def slurp(filename: str) -> bytes:
+    with open(filename, 'rb') as f:
+        return f.read()
 
 if __name__ == '__main__':
     if len(sys.argv) != 2+1 or sys.argv[1] != 'create_multigroup_assgmt':