better error handling in cases where event json changes

1 files changed, 89 insertions, 33 deletions

diff --git a/src/tw/events.rs b/src/tw/events.rs
index afc7fbb..35167a3 100644
--- a/src/tw/events.rs
+++ b/src/tw/events.rs
@@ -13,39 +13,95 @@ pub enum Event {
 }
 
 impl Event {
-    pub fn from_json(structure: serde_json::Map<String, serde_json::Value>) -> Option<Event> {
-        match &structure["event"].as_str().unwrap() {
-            &"follow" => Some(Event::Followed {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned()
-            }),
-            &"unfollow" => Some(Event::Unfollowed {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned()
-            }),
-            &"favorite" => Some(Event::Fav {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned(),
-                twete_id: structure["target_object"]["id_str"].as_str().unwrap().to_owned()
-            }),
-            &"unfavorite" => Some(Event::Unfav {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned(),
-                twete_id: structure["target_object"]["id_str"].as_str().unwrap().to_owned()
-            }),
-            &"favorited_retweet" => Some(Event::Fav_RT {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned(),
-                twete_id: structure["target_object"]["id_str"].as_str().unwrap().to_owned()
-            }),
-            &"retweeted_retweet" => Some(Event::RT_RT {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned(),
-                twete_id: structure["target_object"]["id_str"].as_str().unwrap().to_owned()
-            }),
-            &"quoted_tweet" => Some(Event::Quoted {
-                user_id: structure["source"]["id_str"].as_str().unwrap().to_owned(),
-                twete_id: structure["target_object"]["id_str"].as_str().unwrap().to_owned()
-            }),
-//                &"list_member_added" =>
-//                what about removed?
-//                &"blocked" => Blocked { },
-//                &"unblocked" => Unblocked { },
-            e => { println!("unrecognized event: {}", e); None }
+    fn get_source_id(structure: serde_json::Map<String, serde_json::Value>) -> Result<String, String> {
+        match structure.get("source").and_then(|x| x.get("id_str").and_then(|x| x.as_str())) {
+            Some(id) => Ok(id.to_string()),
+            None => Err("No id_str string at .source.id_str".to_string())
+        }
+    }
+    fn get_source_target_ids(structure: serde_json::Map<String, serde_json::Value>) -> Result<(String, String), String> {
+        match (
+            structure.get("source").and_then(|x| x.get("id_str").and_then(|x| x.as_str())),
+            structure.get("target_obj").and_then(|x| x.get("id_str").and_then(|x| x.as_str()))
+        ) {
+            (Some(source_id), Some(target_id)) => Ok((source_id.to_string(), target_id.to_string())),
+            (None, Some(target_id)) => Err("No id_str string at .source.id_str".to_string()),
+            (Some(target_id), None) => Err("No id_str string at .target_object.id_str".to_string()),
+            (None, None) => Err("No id_str at source or target_object".to_string())
+        }
+    }
+                                                                            // maybe type error
+                                                                            // better? string is ok
+                                                                            // for now..
+    pub fn from_json(structure: serde_json::Map<String, serde_json::Value>) -> Result<Event, String> {
+        match structure.get("event").and_then(|x| x.as_str()).map(|x| x.to_owned()) {
+            Some(event) => {
+                let event_ref: &str = &event;
+                match event_ref {
+                    "follow" =>
+                        Event::get_source_id(structure)
+                            .map(|id_str|
+                                Event::Followed {
+                                    user_id: id_str
+                                }
+                            ),
+                    "unfollow" =>
+                        Event::get_source_id(structure)
+                            .map(|id_str|
+                                Event::Unfollowed {
+                                    user_id: id_str
+                                }
+                            ),
+                    "favorite" =>
+                        Event::get_source_target_ids(structure)
+                            .map(|(source_id, target_id)|
+                                Event::Fav {
+                                    user_id: source_id,
+                                    twete_id: target_id
+                                }
+                            ),
+                    "unfavorite" =>
+                        Event::get_source_target_ids(structure)
+                            .map(|(source_id, target_id)|
+                                Event::Unfav {
+                                    user_id: source_id,
+                                    twete_id: target_id
+                                }
+                            ),
+                    "favorited_retweet" =>
+                        Event::get_source_target_ids(structure)
+                            .map(|(source_id, target_id)|
+                                Event::Fav_RT {
+                                    user_id: source_id,
+                                    twete_id: target_id
+                                }
+                            ),
+                    "retweeted_retweet" =>
+                        Event::get_source_target_ids(structure)
+                            .map(|(source_id, target_id)|
+                                Event::RT_RT {
+                                    user_id: source_id,
+                                    twete_id: target_id
+                                }
+                            ),
+                    "quoted_tweet" =>
+                        Event::get_source_target_ids(structure)
+                            .map(|(source_id, target_id)|
+                                Event::Quoted {
+                                    user_id: source_id,
+                                    twete_id: target_id
+                                }
+                            ),
+        //                "list_member_added" =>
+        //                what about removed?
+        //                "blocked" => Blocked { },
+        //                "unblocked" => Unblocked { },
+                    e => { println!("unrecognized event: {}", e); Err(e.to_string()) }
+                }
+            },
+            None => {
+                Err("No event in event json...".to_string())
+            }
         }
     }
 }