api: Add dc_msg_save_file() which saves file copy at the provided path (

#4309)

- Deprecate dc_msg_get_file(). It's kept for compatibility and now creates a temporary directory
  inside the blobdir, saves a file copy with unmangled filename, and returns its path. In the
  housekeeping we regularly clear these directories.
- Add dc_msg_save_file() which saves file copy at the provided path and fails if file already
  exists. The UI should open the file saving dialog, defaulting to Downloads and original filename,
  when asked to save the file. After confirmation it should call dc_msg_save_file().
- Make dc_msg_get_filename() return the original filename for the use as a default in the file
  saving dialog. For this purpose add Param::Filename in addition to Param::File, to store the
  original filename. Param::Filename is used as an attachment filename in sent emails.
- Use random filename suffixes for blobstorage. Thanks to the added Param::Filename these random
  suffixes is not sent over the network.

deltachat-ffi/deltachat.h

@@ -3986,22 +3986,38 @@ char*           dc_msg_get_text               (const dc_msg_t* msg);
  */
 char*           dc_msg_get_subject            (const dc_msg_t* msg);
 
+
 /**
  * Find out full path, file name and extension of the file associated with a
  * message.
  *
  * Typically files are associated with images, videos, audios, documents.
  * Plain text messages do not have a file.
  *
+ * @deprecated Deprecated 2023-07-22, use dc_msg_save_file() instead.
  * @memberof dc_msg_t
  * @param msg The message object.
  * @return The full path, the file name, and the extension of the file associated with the message.
  *     If there is no file associated with the message, an empty string is returned.
- *     NULL is never returned and the returned value must be released using dc_str_unref().
+ *     On error NULL is returned.
+ *     The returned value must be released using dc_str_unref().
  */
 char*           dc_msg_get_file               (const dc_msg_t* msg);
 
 
+/**
+ * Save file copy at the user-provided path.
+ *
+ * Fails if file already exists at the provided path.
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @param path Destination file path with filename and extension.
+ * @return 0 on failure, 1 on success.
+ */
+int             dc_msg_save_file              (const dc_msg_t* msg, const char* path);
+
+
 /**
  * Get a base file name without the path. The base file name includes the extension; the path
  * is not returned. To get the full path, use dc_msg_get_file().

deltachat-ffi/src/lib.rs

@@ -3310,11 +3310,42 @@ pub unsafe extern "C" fn dc_msg_get_file(msg: *mut dc_msg_t) -> *mut libc::c_cha
     }
     let ffi_msg = &*msg;
     let ctx = &*ffi_msg.context;
-    ffi_msg
-        .message
-        .get_file(ctx)
-        .map(|p| p.to_string_lossy().strdup())
-        .unwrap_or_else(|| "".strdup())
+    let file_path = block_on(async move { ffi_msg.message.get_file(ctx).await });
+    match file_path {
+        Ok(Some(p)) => p.to_string_lossy().strdup(),
+        Ok(None) => "".strdup(),
+        Err(err) => {
+            eprintln!("Failed to get file from message: {err:#}");
+            ptr::null_mut()
+        }
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_save_file(
+    msg: *mut dc_msg_t,
+    path: *const libc::c_char,
+) -> libc::c_int {
+    if msg.is_null() || path.is_null() {
+        eprintln!("ignoring careless call to dc_msg_save_file()");
+        return 0;
+    }
+    let ffi_msg = &*msg;
+    let ctx = &*ffi_msg.context;
+    let path = to_string_lossy(path);
+    let r = block_on(async move {
+        ffi_msg
+            .message
+            .save_file(ctx, &std::path::PathBuf::from(path))
+            .await
+    });
+    match r {
+        Ok(()) => 1,
+        Err(err) => {
+            eprintln!("Failed to save file from message: {err:#}");
+            0
+        }
+    }
 }
 
 #[no_mangle]

deltachat-jsonrpc/src/api/mod.rs

@@ -1,4 +1,5 @@
 use std::collections::BTreeMap;
+use std::path::Path;
 use std::sync::Arc;
 use std::{collections::HashMap, str::FromStr};
 
@@ -1891,19 +1892,21 @@ impl CommandApi {
         );
         let destination_path = account_folder.join("stickers").join(collection);
         fs::create_dir_all(&destination_path).await?;
-        let file = message.get_file(&ctx).context("no file")?;
-        fs::copy(
-            &file,
-            destination_path.join(format!(
-                "{}.{}",
-                msg_id,
-                file.extension()
-                    .unwrap_or_default()
-                    .to_str()
-                    .unwrap_or_default()
-            )),
-        )
-        .await?;
+        let file = message.get_filename().context("no file?")?;
+        message
+            .save_file(
+                &ctx,
+                &destination_path.join(format!(
+                    "{}.{}",
+                    msg_id,
+                    Path::new(&file)
+                        .extension()
+                        .unwrap_or_default()
+                        .to_str()
+                        .unwrap_or_default()
+                )),
+            )
+            .await?;
         Ok(())
     }
 

deltachat-jsonrpc/src/api/types/message.rs

@@ -148,7 +148,7 @@ impl MessageObject {
                             || quote.get_viewtype() == Viewtype::Gif
                             || quote.get_viewtype() == Viewtype::Sticker
                         {
-                            match quote.get_file(context) {
+                            match quote.get_file_path(context) {
                                 Some(path_buf) => path_buf.to_str().map(|s| s.to_owned()),
                                 None => None,
                             }
@@ -221,7 +221,7 @@ impl MessageObject {
 
             setup_code_begin: message.get_setupcodebegin(context).await,
 
-            file: match message.get_file(context) {
+            file: match message.get_file_path(context) {
                 Some(path_buf) => path_buf.to_str().map(|s| s.to_owned()),
                 None => None,
             }, //BLOBS
@@ -416,7 +416,7 @@ impl MessageNotificationInfo {
             Viewtype::Image | Viewtype::Gif | Viewtype::Sticker
         ) {
             message
-                .get_file(context)
+                .get_file_path(context)
                 .map(|path_buf| path_buf.to_str().map(|s| s.to_owned()))
                 .unwrap_or_default()
         } else {

node/test/test.js

@@ -446,7 +446,8 @@ describe('Offline Tests with unconfigured account', function () {
     context.setChatProfileImage(chatId, imagePath)
     const blobPath = context.getChat(chatId).getProfileImage()
     expect(blobPath.startsWith(blobs)).to.be.true
-    expect(blobPath.endsWith(image)).to.be.true
+    expect(blobPath.includes('image')).to.be.true
+    expect(blobPath.endsWith('.jpeg')).to.be.true
 
     context.setChatProfileImage(chatId, null)
     expect(context.getChat(chatId).getProfileImage()).to.be.equal(

python/tests/test_1_online.py

@@ -162,8 +162,9 @@ def test_send_file_twice_unicode_filename_mangling(tmp_path, acfactory, lp):
     ac1, ac2 = acfactory.get_online_accounts(2)
     chat = acfactory.get_accepted_chat(ac1, ac2)
 
-    basename = "somedäüta.html.zip"
-    p = tmp_path / basename
+    basename = "somedäüta"
+    ext = ".html.zip"
+    p = tmp_path / (basename + ext)
     p.write_text("some data")
 
     def send_and_receive_message():
@@ -181,23 +182,26 @@ def send_and_receive_message():
     msg = send_and_receive_message()
     assert msg.text == "withfile"
     assert open(msg.filename).read() == "some data"
-    assert msg.filename.endswith(basename)
+    msg.filename.index(basename)
+    assert msg.filename.endswith(ext)
 
     msg2 = send_and_receive_message()
     assert msg2.text == "withfile"
     assert open(msg2.filename).read() == "some data"
-    assert msg2.filename.endswith("html.zip")
+    msg2.filename.index(basename)
+    assert msg2.filename.endswith(ext)
     assert msg.filename != msg2.filename
 
 
 def test_send_file_html_attachment(tmp_path, acfactory, lp):
     ac1, ac2 = acfactory.get_online_accounts(2)
     chat = acfactory.get_accepted_chat(ac1, ac2)
 
-    basename = "test.html"
+    basename = "test"
+    ext = ".html"
     content = "<html><body>text</body>data"
 
-    p = tmp_path / basename
+    p = tmp_path / (basename + ext)
     # write wrong html to see if core tries to parse it
     # (it shouldn't as it's a file attachment)
     p.write_text(content)
@@ -211,7 +215,8 @@ def test_send_file_html_attachment(tmp_path, acfactory, lp):
     msg = ac2.get_message_by_id(ev.data2)
 
     assert open(msg.filename).read() == content
-    assert msg.filename.endswith(basename)
+    msg.filename.index(basename)
+    assert msg.filename.endswith(ext)
 
 
 def test_html_message(acfactory, lp):

python/tests/test_2_increation.py

@@ -49,10 +49,9 @@ def test_no_increation_copies_to_blobdir(self, tmp_path, acfactory, lp):
         assert str(tmp_path) != ac1.get_blobdir()
         src = tmp_path / "file.txt"
         src.write_text("hello there\n")
-        chat.send_file(str(src))
-
-        blob_src = os.path.join(ac1.get_blobdir(), "file.txt")
-        assert os.path.exists(blob_src), "file.txt not copied to blobdir"
+        msg = chat.send_file(str(src))
+        assert msg.filename.startswith(os.path.join(ac1.get_blobdir(), "file"))
+        assert msg.filename.endswith(".txt")
 
     def test_forward_increation(self, acfactory, data, lp):
         ac1, ac2 = acfactory.get_online_accounts(2)