fix #1077 for unknown senders in a group chat (such as mailer daemons): don't recreate member list and show a special stockstring-ed message advising to hit "more info".

This is the first experiment towards using structs to define the API.
It adds it as a new method on the existing Chat struct.

The types in this struct could improve as well as many other things.
But this is a straight forward translation of the existing json! macro
into a struct.

Cargo.lock

@@ -716,13 +716,12 @@ dependencies = [
 
 [[package]]
 name = "deltachat-provider-database"
-version = "0.3.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.103 (registry+https://github.com/rust-lang/crates.io-index)",
  "yaml-rust 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -739,7 +738,7 @@ name = "deltachat_ffi"
 version = "1.0.0-beta.20"
 dependencies = [
  "deltachat 1.0.0-beta.20",
- "deltachat-provider-database 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "deltachat-provider-database 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "human-panic 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3535,7 +3534,7 @@ dependencies = [
 "checksum darling_macro 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b5a2f4ac4969822c62224815d069952656cadc7084fdca9751e6d959189b72"
 "checksum debug_stub_derive 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "496b7f8a2f853313c3ca370641d7ff3e42c32974fdccda8f0684599ed0a3ff6b"
 "checksum deflate 0.7.20 (registry+https://github.com/rust-lang/crates.io-index)" = "707b6a7b384888a70c8d2e8650b3e60170dfc6a67bb4aa67b6dfca57af4bedb4"
-"checksum deltachat-provider-database 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc18fb898a7bc90565c801d7bd17a4b61478f0da0ea06ecf7f0428bd20242c52"
+"checksum deltachat-provider-database 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "814dba060d9fdc7a989fccdc4810ada9d1c7a1f09131c78e42412bc6c634b93b"
 "checksum derive_builder 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a2658621297f2cf68762a6f7dc0bb7e1ff2cfd6583daef8ee0fed6f7ec468ec0"
 "checksum derive_builder_core 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2791ea3e372c8495c0bc2033991d76b512cd799d07491fbd6890124db9458bef"
 "checksum des 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "74ba5f1b5aee9772379c2670ba81306e65a93c0ee3caade7a1d22b188d88a3af"

deltachat-ffi/Cargo.toml

@@ -16,7 +16,7 @@ crate-type = ["cdylib", "staticlib"]
 
 [dependencies]
 deltachat = { path = "../", default-features = false }
-deltachat-provider-database = "0.3.0"
+deltachat-provider-database = "0.2.1"
 libc = "0.2"
 human-panic = "1.0.1"
 num-traits = "0.2.6"

deltachat-ffi/deltachat.h

@@ -18,6 +18,7 @@ typedef struct _dc_chat     dc_chat_t;
 typedef struct _dc_msg      dc_msg_t;
 typedef struct _dc_contact  dc_contact_t;
 typedef struct _dc_lot      dc_lot_t;
+typedef struct _dc_provider dc_provider_t;
 
 
 /**
@@ -3659,30 +3660,106 @@ int             dc_contact_is_verified       (dc_contact_t* contact);
 
 /**
  * @class dc_provider_t
+ *
+ * Opaque object containing information about one single email provider.
  */
 
+
 /**
- * Get the provider json object for the given domain.
- * For more documentation see https://docs.rs/deltachat-provider-database/
+ * Create a provider struct for the given domain.
  *
  * @memberof dc_provider_t
  * @param domain The domain to get provider info for.
- * @return a provider json object as string. If no provider info is found, an empty string will be returned.
+ * @return a dc_provider_t struct which can be used with the dc_provider_get_*
+ *     accessor functions.  If no provider info is found, NULL will be
+ *     returned.
  */
-char*            dc_provider_json_from_domain           (const char* domain);
+dc_provider_t*  dc_provider_new_from_domain           (const char* domain);
 
 
 /**
- * Get the provider json object for the given email address.
- * For more documentation see https://docs.rs/deltachat-provider-database/
+ * Create a provider struct for the given email address.
  *
  * The provider is extracted from the email address and it's information is returned.
  *
  * @memberof dc_provider_t
  * @param email The user's email address to extract the provider info form.
- * @return a provider json object as string. If no provider info is found, an empty string will be returned.
+ * @return a dc_provider_t struct which can be used with the dc_provider_get_*
+ *     accessor functions.  If no provider info is found, NULL will be
+ *     returned.
  */
-char*            dc_provider_json_from_email           (const char* email);
+dc_provider_t*  dc_provider_new_from_email            (const char* email);
+
+
+/**
+ * URL of the overview page.
+ *
+ * This URL allows linking to the providers page on providers.delta.chat.
+ *
+ * @memberof dc_provider_t
+ * @param provider The dc_provider_t struct.
+ * @return A string which must be released using dc_str_unref().
+ */
+char*           dc_provider_get_overview_page         (const dc_provider_t* provider);
+
+
+/**
+ * The provider's name.
+ *
+ * The name of the provider, e.g. "POSTEO".
+ *
+ * @memberof dc_provider_t
+ * @param provider The dc_provider_t struct.
+ * @return A string which must be released using dc_str_unref().
+ */
+char*           dc_provider_get_name                  (const dc_provider_t* provider);
+
+
+/**
+ * The markdown content of the providers page.
+ *
+ * This contains the preparation steps or additional information if the status
+ * is @ref DC_PROVIDER_STATUS_BROKEN.
+ *
+ * @memberof dc_provider_t
+ * @param provider The dc_provider_t struct.
+ * @return A string which must be released using dc_str_unref().
+ */
+char*           dc_provider_get_markdown              (const dc_provider_t* provider);
+
+
+/**
+ * Date of when the state was last checked/updated.
+ *
+ * This is returned as a string.
+ *
+ * @memberof dc_provider_t
+ * @param provider The dc_provider_t struct.
+ * @return A string which must be released using dc_str_unref().
+ */
+char*           dc_provider_get_status_date           (const dc_provider_t* provider);
+
+
+/**
+ * Whether DC works with this provider.
+ *
+ * Can be one of @ref DC_PROVIDER_STATUS_OK, @ref
+ * DC_PROVIDER_STATUS_PREPARATION and @ref DC_PROVIDER_STATUS_BROKEN.
+ *
+ * @memberof dc_provider_t
+ * @param provider The dc_provider_t struct.
+ * @return The status as a constant number.
+ */
+int             dc_provider_get_status                (const dc_provider_t* provider);
+
+
+/**
+ * Free the provider info struct.
+ *
+ * @memberof dc_provider_t
+ * @param provider The dc_provider_t struct.
+ */
+void            dc_provider_unref                     (const dc_provider_t* provider);
 
 
 /**
@@ -4398,6 +4475,41 @@ void            dc_array_add_id              (dc_array_t*, uint32_t); // depreca
 #define DC_SHOW_EMAILS_ALL               2
 
 
+/**
+ * @defgroup DC_PROVIDER_STATUS DC_PROVIDER_STATUS
+ *
+ * These constants are used as return values for dc_provider_get_status().
+ *
+ * @addtogroup DC_PROVIDER_STATUS
+ * @{
+ */
+
+/**
+ * Provider status returned by dc_provider_get_status().
+ *
+ * Works right out of the box without any preperation steps needed
+ */
+#define         DC_PROVIDER_STATUS_OK           1
+
+/**
+ * Provider status returned by dc_provider_get_status().
+ *
+ * Works, but preparation steps are needed
+ */
+#define         DC_PROVIDER_STATUS_PREPARATION  2
+
+/**
+ * Provider status returned by dc_provider_get_status().
+ *
+ * Doesn't work (too unstable to use falls also in this category)
+ */
+#define         DC_PROVIDER_STATUS_BROKEN       3
+
+/**
+ * @}
+ */
+
+
 /*
  * TODO: Strings need some doumentation about used placeholders.
  *

deltachat-ffi/src/lib.rs

@@ -10,6 +10,7 @@
 #[macro_use]
 extern crate human_panic;
 extern crate num_traits;
+extern crate serde_json;
 
 use std::collections::HashMap;
 use std::convert::TryInto;
@@ -2390,12 +2391,27 @@ pub unsafe extern "C" fn dc_chat_get_info_json(
     }
     let ffi_context = &*context;
     ffi_context
-        .with_inner(|ctx| match chat::get_info_json(ctx, chat_id) {
-            Ok(s) => s.strdup(),
-            Err(err) => {
-                error!(ctx, "get_info_json({}) returned: {}", chat_id, err);
-                return "".strdup();
-            }
+        .with_inner(|ctx| {
+            let chat = match chat::Chat::load_from_db(ctx, chat_id) {
+                Ok(chat) => chat,
+                Err(err) => {
+                    error!(ctx, "dc_get_chat_info_json() failed to load chat: {}", err);
+                    return "".strdup();
+                }
+            };
+            let info = match chat.get_info(ctx) {
+                Ok(info) => info,
+                Err(err) => {
+                    error!(
+                        ctx,
+                        "dc_get_chat_info_json() failed to get chat info: {}", err
+                    );
+                    return "".strdup();
+                }
+            };
+            serde_json::to_string(&info)
+                .unwrap_or_log_default(ctx, "dc_get_chat_info_json() failed to serialise to json")
+                .strdup()
         })
         .unwrap_or_else(|_| "".strdup())
 }

deltachat-ffi/src/providers.rs

@@ -1,35 +1,93 @@
 extern crate deltachat_provider_database;
 
+use std::ptr;
+
 use crate::string::{to_string_lossy, StrExt};
+use deltachat_provider_database::StatusState;
 
 #[no_mangle]
 pub type dc_provider_t = deltachat_provider_database::Provider;
 
 #[no_mangle]
-pub unsafe extern "C" fn dc_provider_json_from_domain(
+pub unsafe extern "C" fn dc_provider_new_from_domain(
     domain: *const libc::c_char,
-) -> *mut libc::c_char {
-    let domain = to_string_lossy(domain);
-    match deltachat_provider_database::get_provider_info(&domain) {
-        Some(provider) => serde_json::to_string(provider)
-            .unwrap_or("".to_owned())
-            .strdup(),
-        None => "".strdup(),
+) -> *const dc_provider_t {
+    match deltachat_provider_database::get_provider_info(&to_string_lossy(domain)) {
+        Some(provider) => provider,
+        None => ptr::null(),
     }
 }
 
 #[no_mangle]
-pub unsafe extern "C" fn dc_provider_json_from_email(
+pub unsafe extern "C" fn dc_provider_new_from_email(
     email: *const libc::c_char,
-) -> *mut libc::c_char {
+) -> *const dc_provider_t {
     let email = to_string_lossy(email);
     let domain = deltachat_provider_database::get_domain_from_email(&email);
     match deltachat_provider_database::get_provider_info(domain) {
-        Some(provider) => serde_json::to_string(provider)
-            .unwrap_or("".to_owned())
-            .strdup(),
-        None => "".strdup(),
+        Some(provider) => provider,
+        None => ptr::null(),
     }
 }
 
+macro_rules! null_guard {
+    ($context:tt) => {
+        if $context.is_null() {
+            return ptr::null_mut() as *mut libc::c_char;
+        }
+    };
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_provider_get_overview_page(
+    provider: *const dc_provider_t,
+) -> *mut libc::c_char {
+    null_guard!(provider);
+    format!(
+        "{}/{}",
+        deltachat_provider_database::PROVIDER_OVERVIEW_URL,
+        (*provider).overview_page
+    )
+    .strdup()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_provider_get_name(provider: *const dc_provider_t) -> *mut libc::c_char {
+    null_guard!(provider);
+    (*provider).name.strdup()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_provider_get_markdown(
+    provider: *const dc_provider_t,
+) -> *mut libc::c_char {
+    null_guard!(provider);
+    (*provider).markdown.strdup()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_provider_get_status_date(
+    provider: *const dc_provider_t,
+) -> *mut libc::c_char {
+    null_guard!(provider);
+    (*provider).status.date.strdup()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_provider_get_status(provider: *const dc_provider_t) -> u32 {
+    if provider.is_null() {
+        return 0;
+    }
+    match (*provider).status.state {
+        StatusState::OK => 1,
+        StatusState::PREPARATION => 2,
+        StatusState::BROKEN => 3,
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_provider_unref(_provider: *const dc_provider_t) {
+    ()
+}
+
 // TODO expose general provider overview url?

python/src/deltachat/provider.py

@@ -1,8 +1,7 @@
 """Provider info class."""
 
-from .capi import lib
+from .capi import ffi, lib
 from .cutil import as_dc_charpointer, from_dc_charpointer
-import json
 
 
 class ProviderNotFoundError(Exception):
@@ -17,12 +16,13 @@ class Provider(object):
     """
 
     def __init__(self, domain):
-        provider = from_dc_charpointer(
-            lib.dc_provider_json_from_domain(as_dc_charpointer(domain))
+        provider = ffi.gc(
+            lib.dc_provider_new_from_domain(as_dc_charpointer(domain)),
+            lib.dc_provider_unref,
         )
-        if provider == "":
+        if provider == ffi.NULL:
             raise ProviderNotFoundError("Provider not found")
-        self._provider = json.loads(provider)
+        self._provider = provider
 
     @classmethod
     def from_email(cls, email):
@@ -35,30 +35,33 @@ class Provider(object):
     @property
     def overview_page(self):
         """URL to the overview page of the provider on providers.delta.chat."""
-        return "https://providers.delta.chat/" + self._provider['overview_page']
+        return from_dc_charpointer(
+            lib.dc_provider_get_overview_page(self._provider))
 
     @property
     def name(self):
         """The name of the provider."""
-        return self._provider['name']
+        return from_dc_charpointer(lib.dc_provider_get_name(self._provider))
 
     @property
     def markdown(self):
         """Content of the information page, formatted as markdown."""
-        return self._provider['markdown']
+        return from_dc_charpointer(
+            lib.dc_provider_get_markdown(self._provider))
 
     @property
     def status_date(self):
         """The date the provider info was last updated, as a string."""
-        return self._provider['status']['date']
+        return from_dc_charpointer(
+            lib.dc_provider_get_status_date(self._provider))
 
     @property
     def status(self):
         """The status of the provider information.
 
-        This is
-        :attr:`"OK"`,
-        :attr:`"PREPARATION"` or
-        :attr:`"BROKEN"`.
+        This is one of the
+        :attr:`deltachat.const.DC_PROVIDER_STATUS_OK`,
+        :attr:`deltachat.const.DC_PROVIDER_STATUS_PREPARATION` or
+        :attr:`deltachat.const.DC_PROVIDER_STATUS_BROKEN` constants.
         """
-        return self._provider['status']['state']
+        return lib.dc_provider_get_status(self._provider)

python/tests/test_lowlevel.py

@@ -3,7 +3,6 @@ from deltachat import capi, cutil, const, set_context_callback, clear_context_ca
 from deltachat.capi import ffi
 from deltachat.capi import lib
 from deltachat.account import EventLogger
-import json
 
 
 def test_empty_context():
@@ -104,23 +103,18 @@ def test_get_special_message_id_returns_empty_message(acfactory):
 
 
 def test_provider_info():
-    provider_json = cutil.from_dc_charpointer(
-        lib.dc_provider_json_from_email(cutil.as_dc_charpointer("ex@example.com"))
-    )
-    provider = json.loads(provider_json)
-
-    assert provider['overview_page'] == "example.com"
-    assert provider['name'] == "Example"
-    assert provider['markdown'] == "\n..."
-    assert provider['status']['date'] == "2018-09"
-    assert provider['status']['state'] == "PREPARATION"
+    provider = lib.dc_provider_new_from_email(cutil.as_dc_charpointer("ex@example.com"))
+    assert cutil.from_dc_charpointer(
+        lib.dc_provider_get_overview_page(provider)
+    ) == "https://providers.delta.chat/example.com"
+    assert cutil.from_dc_charpointer(lib.dc_provider_get_name(provider)) == "Example"
+    assert cutil.from_dc_charpointer(lib.dc_provider_get_markdown(provider)) == "\n..."
+    assert cutil.from_dc_charpointer(lib.dc_provider_get_status_date(provider)) == "2018-09"
+    assert lib.dc_provider_get_status(provider) == const.DC_PROVIDER_STATUS_PREPARATION
 
 
 def test_provider_info_none():
-    provider_json = cutil.from_dc_charpointer(
-        lib.dc_provider_json_from_email(cutil.as_dc_charpointer("email@unexistent.no"))
-    )
-    assert provider_json == ""
+    assert lib.dc_provider_new_from_email(cutil.as_dc_charpointer("email@unexistent.no")) == ffi.NULL
 
 
 def test_get_info_closed():

python/tests/test_provider_info.py

@@ -1,5 +1,6 @@
 import pytest
 
+from deltachat import const
 from deltachat import provider
 
 
@@ -9,7 +10,7 @@ def test_provider_info_from_email():
     assert example.name == "Example"
     assert example.markdown == "\n..."
     assert example.status_date == "2018-09"
-    assert example.status == "PREPARATION"
+    assert example.status == const.DC_PROVIDER_STATUS_PREPARATION
 
 
 def test_provider_info_from_domain():
@@ -18,7 +19,7 @@ def test_provider_info_from_domain():
     assert example.name == "Example"
     assert example.markdown == "\n..."
     assert example.status_date == "2018-09"
-    assert example.status == "PREPARATION"
+    assert example.status == const.DC_PROVIDER_STATUS_PREPARATION
 
 
 def test_provider_info_none():

src/chat.rs

@@ -4,7 +4,7 @@ use std::path::{Path, PathBuf};
 
 use itertools::Itertools;
 use num_traits::FromPrimitive;
-use serde_json::json;
+use serde::{Deserialize, Serialize};
 
 use crate::blob::{BlobError, BlobObject};
 use crate::chatlist::*;
@@ -240,6 +240,30 @@ impl Chat {
         color
     }
 
+    /// Returns a struct describing the current state of the chat.
+    ///
+    /// This is somewhat experimental, even more so than the rest of
+    /// deltachat, and the data returned is still subject to change.
+    pub fn get_info(&self, context: &Context) -> Result<ChatInfo, Error> {
+        let draft = match get_draft(context, self.id)? {
+            Some(message) => message.text.unwrap_or_else(String::new),
+            _ => String::new(),
+        };
+        Ok(ChatInfo {
+            id: self.id,
+            type_: self.typ as u32,
+            name: self.name.clone(),
+            archived: self.archived,
+            param: self.param.to_string(),
+            gossiped_timestamp: self.get_gossiped_timestamp(context),
+            is_sending_locations: self.is_sending_locations,
+            color: self.get_color(context),
+            profile_image: self.get_profile_image(context).unwrap_or_else(PathBuf::new),
+            subtitle: self.get_subtitle(context),
+            draft,
+        })
+    }
+
     /// Returns true if the chat is archived.
     pub fn is_archived(&self) -> bool {
         self.archived
@@ -497,6 +521,68 @@ impl Chat {
     }
 }
 
+/// The current state of a chat.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct ChatInfo {
+    /// The chat ID.
+    pub id: u32,
+
+    /// The type of chat as a `u32` representation of [Chattype].
+    ///
+    /// On the C API this number is one of the
+    /// `DC_CHAT_TYPE_UNDEFINED`, `DC_CHAT_TYPE_SINGLE`,
+    /// `DC_CHAT_TYPE_GROUP` or `DC_CHAT_TYPE_VERIFIED_GROUP`
+    /// constants.
+    #[serde(rename = "type")]
+    pub type_: u32,
+
+    /// The name of the chat.
+    pub name: String,
+
+    /// Whether the chat is archived.
+    pub archived: bool,
+
+    /// The "params" of the chat.
+    ///
+    /// This is the string-serialised version of [Params] currently.
+    pub param: String,
+
+    /// Something to do with gossiping and timestamps?
+    pub gossiped_timestamp: i64,
+
+    /// Whether this chat is currently sending location-stream messages.
+    pub is_sending_locations: bool,
+
+    /// Colour this chat should be represented in by the UI.
+    ///
+    /// Yes, spelling colour is hard.
+    pub color: u32,
+
+    /// The path to the profile image.
+    ///
+    /// If there is no profile image set this will be an empty string
+    /// currently.
+    pub profile_image: PathBuf,
+
+    /// Subtitle for the chat.
+    pub subtitle: String,
+
+    /// The draft message text.
+    ///
+    /// If the chat has not draft this is an empty string.
+    ///
+    /// TODO: This doesn't seem rich enough, it can not handle drafts
+    ///       which contain non-text parts.  Perhaps it should be a
+    ///       simple `has_draft` bool instead.
+    pub draft: String,
+    // ToDo:
+    // - [ ] deaddrop,
+    // - [ ] summary,
+    // - [ ] lastUpdated,
+    // - [ ] freshMessageCounter,
+    // - [ ] email
+}
+
 /// Create a normal chat or a group chat by a messages ID that comes typically
 /// from the deaddrop, DC_CHAT_ID_DEADDROP (1).
 ///
@@ -1990,54 +2076,6 @@ pub fn forward_msgs(context: &Context, msg_ids: &[MsgId], chat_id: u32) -> Resul
     Ok(())
 }
 
-pub fn get_info_json(context: &Context, chat_id: u32) -> Result<String, Error> {
-    let chat = Chat::load_from_db(context, chat_id).unwrap();
-
-    // ToDo:
-    // - [x] id
-    // - [x] type
-    // - [x] name
-    // - [x] archived
-    // - [x] color
-    // - [x] profileImage
-    // - [x] subtitle
-    // - [x] draft,
-    // - [ ] deaddrop,
-    // - [ ] summary,
-    // - [ ] lastUpdated,
-    // - [ ] freshMessageCounter,
-    // - [ ] email
-
-    let profile_image = match chat.get_profile_image(context) {
-        Some(path) => path.into_os_string().into_string().unwrap(),
-        None => "".to_string(),
-    };
-
-    let draft = match get_draft(context, chat_id) {
-        Ok(message) => match message {
-            Some(m) => m.text.unwrap_or_else(|| "".to_string()),
-            None => "".to_string(),
-        },
-        Err(_) => "".to_string(),
-    };
-
-    let s = json!({
-         "id": chat.id,
-         "type": chat.typ as u32,
-         "name": chat.name,
-         "archived": chat.archived,
-         "param": chat.param.to_string(),
-         "gossiped_timestamp": chat.get_gossiped_timestamp(context),
-         "is_sending_locations": chat.is_sending_locations,
-         "color": chat.get_color(context),
-         "profile_image": profile_image,
-         "subtitle": chat.get_subtitle(context),
-         "draft": draft
-    });
-
-    Ok(s.to_string())
-}
-
 pub fn get_chat_contact_cnt(context: &Context, chat_id: u32) -> usize {
     context
         .sql
@@ -2192,8 +2230,41 @@ pub fn add_info_msg(context: &Context, chat_id: u32, text: impl AsRef<str>) {
 mod tests {
     use super::*;
 
+    use crate::contact::Contact;
     use crate::test_utils::*;
 
+    #[test]
+    fn test_chat_info() {
+        let t = dummy_context();
+        let bob = Contact::create(&t.ctx, "bob", "bob@example.com").unwrap();
+        let chat_id = create_by_contact_id(&t.ctx, bob).unwrap();
+        let chat = Chat::load_from_db(&t.ctx, chat_id).unwrap();
+        let info = chat.get_info(&t.ctx).unwrap();
+
+        // Ensure we can serialise this.
+        println!("{}", serde_json::to_string_pretty(&info).unwrap());
+
+        let expected = r#"
+            {
+                "id": 10,
+                "type": 100,
+                "name": "bob",
+                "archived": false,
+                "param": "",
+                "gossiped_timestamp": 0,
+                "is_sending_locations": false,
+                "color": 15895624,
+                "profile_image": "",
+                "subtitle": "bob@example.com",
+                "draft": ""
+            }
+        "#;
+
+        // Ensure we can deserialise this.
+        let loaded: ChatInfo = serde_json::from_str(expected).unwrap();
+        assert_eq!(info, loaded);
+    }
+
     #[test]
     fn test_get_draft_no_draft() {
         let t = dummy_context();

src/dc_receive_imf.rs

@@ -877,10 +877,15 @@ fn create_or_lookup_group(
                 mime_parser.repl_msg_by_error(s);
             }
         }
-        // check if the sender is a member of the existing group -
-        // if not, we'll recreate the group list
         if !chat::is_contact_in_chat(context, chat_id, from_id as u32) {
-            recreate_member_list = true;
+            // The From-address is not part of this group.
+            // It could be a new user or a DSN from a mailer-daemon.
+            // in any case we do not want to recreate the member list
+            // but still show the message as part of the chat.
+            // After all, the sender has a reference/in-reply-to that
+            // points to this chat.
+            let s = context.stock_str(StockMessage::UnknownSenderForChat);
+            mime_parser.repl_msg_by_error(s.to_string());
         }
     }
 

src/mimefactory.rs

@@ -1002,6 +1002,21 @@ impl<'a, 'b> MimeFactory<'a, 'b> {
     }
 }
 
+/// Returns base64-encoded buffer `buf` split into 78-bytes long
+/// chunks separated by CRLF.
+///
+/// This line length limit is an
+/// [RFC5322 requirement](https://tools.ietf.org/html/rfc5322#section-2.1.1).
+fn wrapped_base64_encode(buf: &[u8]) -> String {
+    let base64 = base64::encode(&buf);
+    let mut chars = base64.chars();
+    (0..)
+        .map(|_| chars.by_ref().take(78).collect::<String>())
+        .take_while(|s| !s.is_empty())
+        .collect::<Vec<_>>()
+        .join("\r\n")
+}
+
 fn build_body_file(
     context: &Context,
     msg: &Message,
@@ -1062,7 +1077,7 @@ fn build_body_file(
     };
 
     let body = std::fs::read(blob.to_abs_path())?;
-    let encoded_body = base64::encode(&body);
+    let encoded_body = wrapped_base64_encode(&body);
 
     let mail = PartBuilder::new()
         .content_type(&mimetype)
@@ -1084,7 +1099,7 @@ fn build_selfavatar_file(context: &Context, path: String) -> Result<(PartBuilder
         None => mime::APPLICATION_OCTET_STREAM,
     };
     let body = std::fs::read(blob.to_abs_path())?;
-    let encoded_body = base64::encode(&body);
+    let encoded_body = wrapped_base64_encode(&body);
 
     let part = PartBuilder::new()
         .content_type(&mimetype)
@@ -1203,4 +1218,13 @@ mod tests {
             "<123@q> <456@d>".to_string()
         );
     }
+
+    #[test]
+    fn test_wrapped_base64_encode() {
+        let input = b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
+        let output =
+            "QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQU\r\n\
+             FBQUFBQUFBQQ==";
+        assert_eq!(wrapped_base64_encode(input), output);
+    }
 }

src/stock.rs

@@ -185,6 +185,9 @@ pub enum StockMessage {
                     Recipients don't need to install Delta Chat, visit websites or sign up anywhere - \
                     however, of course, if they like, you may point them to 👉 https://get.delta.chat"))]
     WelcomeMessage = 71,
+
+    #[strum(props(fallback = "Unknown Sender for this chat. See 'info' for more details."))]
+    UnknownSenderForChat = 72,
 }
 
 /*