Paginate the outbox responses. Fixes #669 (#681)

* Paginate the outbox responses. Fixes #669

* Address Ana's review

* Make outbox_fetch page through instance outboxes

* Fix infinite loop in fetch_outbox

* Fix off by one

plume-models/src/blogs.rs

@@ -1,4 +1,9 @@
-use activitypub::{actor::Group, collection::OrderedCollection, object::Image, CustomObject};
+use activitypub::{
+    actor::Group,
+    collection::{OrderedCollection, OrderedCollectionPage},
+    object::Image,
+    CustomObject,
+};
 use chrono::NaiveDateTime;
 use diesel::{self, ExpressionMethods, OptionalExtension, QueryDsl, RunQueryDsl, SaveChangesDsl};
 use openssl::{
@@ -22,7 +27,7 @@ use safe_string::SafeString;
 use schema::blogs;
 use search::Searcher;
 use users::User;
-use {Connection, Error, PlumeRocket, Result};
+use {ap_url, Connection, Error, PlumeRocket, Result, ITEMS_PER_PAGE};
 
 pub type CustomGroup = CustomObject<ApSignature, Group>;
 
@@ -220,12 +225,49 @@ impl Blog {
         coll.collection_props.items = serde_json::to_value(self.get_activities(conn)?)?;
         coll.collection_props
             .set_total_items_u64(self.get_activities(conn)?.len() as u64)?;
+        coll.collection_props
+            .set_first_link(Id::new(ap_url(&format!("{}?page=1", &self.outbox_url))))?;
+        coll.collection_props
+            .set_last_link(Id::new(ap_url(&format!(
+                "{}?page={}",
+                &self.outbox_url,
+                (self.get_activities(conn)?.len() as u64 + ITEMS_PER_PAGE as u64 - 1) as u64
+                    / ITEMS_PER_PAGE as u64
+            ))))?;
+        Ok(ActivityStream::new(coll))
+    }
+    pub fn outbox_page(
+        &self,
+        conn: &Connection,
+        (min, max): (i32, i32),
+    ) -> Result<ActivityStream<OrderedCollectionPage>> {
+        let mut coll = OrderedCollectionPage::default();
+        let acts = self.get_activity_page(&conn, (min, max))?;
+        //This still doesn't do anything because the outbox
+        //doesn't do anything yet
+        coll.collection_page_props.set_next_link(Id::new(&format!(
+            "{}?page={}",
+            &self.outbox_url,
+            min / ITEMS_PER_PAGE + 1
+        )))?;
+        coll.collection_page_props.set_prev_link(Id::new(&format!(
+            "{}?page={}",
+            &self.outbox_url,
+            min / ITEMS_PER_PAGE - 1
+        )))?;
+        coll.collection_props.items = serde_json::to_value(acts)?;
         Ok(ActivityStream::new(coll))
     }
-
     fn get_activities(&self, _conn: &Connection) -> Result<Vec<serde_json::Value>> {
         Ok(vec![])
     }
+    fn get_activity_page(
+        &self,
+        _conn: &Connection,
+        (_min, _max): (i32, i32),
+    ) -> Result<Vec<serde_json::Value>> {
+        Ok(vec![])
+    }
 
     pub fn get_keypair(&self) -> Result<PKey<Private>> {
         PKey::from_rsa(Rsa::private_key_from_pem(