feat: update.href api

add `update.href` property option to update objects
send via `Context::send_webxdc_status_update()`.

when set together with `update.info`,
UI can implement the info message as a link that is passed to the webxdc
via `window.location.href`.
for that purpose, UI will read the link back from `Message::get_webxdc_href()`.

Practically,
this allows e.g. an calendar.xdc
to emits clickable update messages
opening the calendar at the correct date.

Author: r10s

deltachat-ffi/deltachat.h

@@ -4518,6 +4518,24 @@ int             dc_msg_get_info_type          (const dc_msg_t* msg);
 #define         DC_INFO_INVALID_UNENCRYPTED_MAIL  13
 #define         DC_INFO_WEBXDC_INFO_MESSAGE       32
 
+
+/**
+ * Get link attached to an webxdc info message.
+ * The info message needs to be of type DC_INFO_WEBXDC_INFO_MESSAGE.
+ *
+ * Typically, this is used to set `document.location.href` in JS land.
+ *
+ * Webxdc apps can define the link by setting `update.href` when sending and update,
+ * see dc_send_webxdc_status_update().
+ *
+ * @memberof dc_msg_t
+ * @param msg The info message object.
+ *     Not: the webxdc instance.
+ * @return The link to be set to `document.location.href` in JS land.
+ *     Returns NULL if there is no link attached to the info message and on errors.
+ */
+char*           dc_msg_get_webxdc_href        (const dc_msg_t* msg);
+
 /**
  * Check if a message is still in creation. A message is in creation between
  * the calls to dc_prepare_msg() and dc_send_msg().

deltachat-ffi/src/lib.rs

@@ -3687,6 +3687,20 @@ pub unsafe extern "C" fn dc_msg_get_info_type(msg: *mut dc_msg_t) -> libc::c_int
     ffi_msg.message.get_info_type() as libc::c_int
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_get_webxdc_href(msg: *mut dc_msg_t) -> *mut libc::c_char {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_get_webxdc_href()");
+        return "".strdup();
+    }
+
+    let ffi_msg = &*msg;
+    match ffi_msg.message.get_webxdc_href() {
+        Some(str) => str.strdup(),
+        None => ptr::null_mut(),
+    }
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn dc_msg_is_increation(msg: *mut dc_msg_t) -> libc::c_int {
     if msg.is_null() {

src/debug_logging.rs

@@ -60,6 +60,7 @@ pub async fn debug_logging_loop(context: &Context, events: Receiver<DebugEventLo
                         "time": time,
                     }),
                     info: None,
+                    href: None,
                     summary: None,
                     document: None,
                     uid: None,

src/webxdc.rs

@@ -165,6 +165,11 @@ pub struct StatusUpdateItem {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub info: Option<String>,
 
+    /// Optional link the info message will point to.
+    /// Used to set `window.location.href` in JS land.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub href: Option<String>,
+
     /// The new name of the editing document.
     /// This is not needed if the webxdc doesn't edit documents.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -353,19 +358,22 @@ impl Context {
 
         if can_info_msg {
             if let Some(ref info) = status_update_item.info {
-                if let Some(info_msg_id) = self
+                let info_msg_id = self
                     .get_overwritable_info_msg_id(&instance, from_id)
-                    .await?
-                {
-                    chat::update_msg_text_and_timestamp(
-                        self,
-                        instance.chat_id,
-                        info_msg_id,
-                        info.as_str(),
-                        timestamp,
-                    )
                     .await?;
-                    notify_msg_id = info_msg_id;
+
+                if info_msg_id.is_some() && !status_update_item.href.is_some() {
+                    if let Some(info_msg_id) = info_msg_id {
+                        chat::update_msg_text_and_timestamp(
+                            self,
+                            instance.chat_id,
+                            info_msg_id,
+                            info.as_str(),
+                            timestamp,
+                        )
+                        .await?;
+                        notify_msg_id = info_msg_id;
+                    }
                 } else {
                     notify_msg_id = chat::add_info_msg_with_cmd(
                         self,
@@ -380,6 +388,12 @@ impl Context {
                     .await?;
                 }
                 notify_text = info.to_string();
+
+                if let Some(href) = status_update_item.href {
+                    let mut notify_msg = Message::load_from_db(self, notify_msg_id).await?;
+                    notify_msg.param.set(Param::Arg, href);
+                    notify_msg.update_param(self).await?;
+                }
             }
         }
 
@@ -944,6 +958,18 @@ impl Message {
         let hash = Sha256::digest(data.as_bytes());
         Ok(format!("{:x}", hash))
     }
+
+    /// Get link attached to an info message.
+    ///
+    /// The info message needs to be of type SystemMessage::WebxdcInfoMessage.
+    /// Typically, this is used to start the corresponding
+    //  with `window.location.href` set in JS land.
+    pub fn get_webxdc_href(&self) -> Option<String> {
+        let Some(href) = self.param.get(Param::Arg) else {
+            return None;
+        };
+        Some(href.to_string())
+    }
 }
 
 #[cfg(test)]
@@ -1457,6 +1483,7 @@ mod tests {
                 StatusUpdateItem {
                     payload: json!({"foo": "bar"}),
                     info: None,
+                    href: None,
                     document: None,
                     summary: None,
                     uid: Some("iecie2Ze".to_string()),
@@ -1482,6 +1509,7 @@ mod tests {
                 StatusUpdateItem {
                     payload: json!({"nothing": "this should be ignored"}),
                     info: None,
+                    href: None,
                     document: None,
                     summary: None,
                     uid: Some("iecie2Ze".to_string()),
@@ -1516,6 +1544,7 @@ mod tests {
                 StatusUpdateItem {
                     payload: json!({"foo2": "bar2"}),
                     info: None,
+                    href: None,
                     document: None,
                     summary: None,
                     uid: None,
@@ -1536,6 +1565,7 @@ mod tests {
             StatusUpdateItem {
                 payload: Value::Bool(true),
                 info: None,
+                href: None,
                 document: None,
                 summary: None,
                 uid: None,
@@ -3069,4 +3099,38 @@ sth_for_the = "future""#
 
         Ok(())
     }
+
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_webxdc_href() -> Result<()> {
+        let mut tcm = TestContextManager::new();
+        let alice = tcm.alice().await;
+        let bob = tcm.bob().await;
+
+        let grp_id = alice
+            .create_group_with_members(ProtectionStatus::Unprotected, "grp", &[&bob])
+            .await;
+        let instance = send_webxdc_instance(&alice, grp_id).await?;
+        let sent1 = alice.pop_sent_msg().await;
+
+        alice
+            .send_webxdc_status_update(
+                instance.id,
+                r##"{"payload": "my deeplink data", "info": "my move!", "href": "#foobar"}"##,
+                "d",
+            )
+            .await?;
+        alice.flush_status_updates().await?;
+        let sent2 = alice.pop_sent_msg().await;
+        let info_msg = alice.get_last_msg().await;
+        assert!(info_msg.is_info());
+        assert_eq!(info_msg.get_webxdc_href(), Some("#foobar".to_string()));
+
+        bob.recv_msg(&sent1).await;
+        bob.recv_msg_trash(&sent2).await;
+        let info_msg = bob.get_last_msg().await;
+        assert!(info_msg.is_info());
+        assert_eq!(info_msg.get_webxdc_href(), Some("#foobar".to_string()));
+
+        Ok(())
+    }
 }

src/webxdc/maps_integration.rs

@@ -146,6 +146,7 @@ pub(crate) async fn intercept_get_updates(
                 item: StatusUpdateItem {
                     payload: serde_json::to_value(location_item)?,
                     info: None,
+                    href: None,
                     document: None,
                     summary: None,
                     uid: None,