Add a ShareMap across contexts

The context now exposes, through the Client, a `data` field, which can
be accessed safely across contexts. This allows for a custom "shared
state" without the need for (ab)using lazy-static.rs.

Refer to example 06 for an example on how to use shared data.

7 files changed, 147 insertions, 44 deletions

diff --git a/Cargo.toml b/Cargo.toml
index be64dfd..78caa80 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,6 +21,7 @@ lazy_static = "0.2"
 log = "0.3"
 serde_json = "0.8"
 time = "0.1"
+typemap = "0.3"
 websocket = "0.17"
 
 [dependencies.cookie]
diff --git a/examples/06_command_framework/Cargo.toml b/examples/06_command_framework/Cargo.toml
index 481dd6f..a73f940 100644
--- a/examples/06_command_framework/Cargo.toml
+++ b/examples/06_command_framework/Cargo.toml
@@ -3,6 +3,9 @@ name = "06_command_framework"
 version = "0.1.0"
 authors = ["my name <[email protected]>"]
 
+[dependencies]
+typemap = "0.3"
+
 [dependencies.serenity]
 features = ["framework", "methods"]
 version = "0.1"
diff --git a/examples/06_command_framework/src/main.rs b/examples/06_command_framework/src/main.rs
index b399dff..0943d81 100644
--- a/examples/06_command_framework/src/main.rs
+++ b/examples/06_command_framework/src/main.rs
@@ -10,11 +10,21 @@
 
 #[macro_use]
 extern crate serenity;
+extern crate typemap;
 
 use serenity::client::Context;
 use serenity::Client;
 use serenity::model::Message;
+use std::collections::HashMap;
 use std::env;
+use std::fmt::Write;
+use typemap::Key;
+
+struct CommandCounter;
+
+impl Key for CommandCounter {
+    type Value = HashMap<String, u64>;
+}
 
 fn main() {
     // Configure the client with your Discord bot token in the environment.
@@ -22,6 +32,11 @@ fn main() {
         .expect("Expected a token in the environment");
     let mut client = Client::login_bot(&token);
 
+    {
+        let mut data = client.data.lock().unwrap();
+        data.insert::<CommandCounter>(HashMap::default());
+    }
+
     client.on_ready(|_context, ready| {
         println!("{} is connected!", ready.user.name);
     });
@@ -51,16 +66,26 @@ fn main() {
         // You can not use this to determine whether a command should be
         // executed. Instead, `set_check` is provided to give you this
         // functionality.
-        .before(|_context, message, command_name| {
+        .before(|context, message, command_name| {
             println!("Got command '{}' by user '{}'",
                      command_name,
                      message.author.name);
+
+            // Increment the number of times this command has been run once. If
+            // the command's name does not exist in the counter, add a default
+            // value of 0.
+            let mut data = context.data.lock().unwrap();
+            let counter = data.get_mut::<CommandCounter>().unwrap();
+            let entry = counter.entry(command_name.clone()).or_insert(0);
+            *entry += 1;
         })
         // Very similar to `before`, except this will be called directly _after_
         // command execution.
         .after(|_context, _message, command_name| {
             println!("Processed command '{}'", command_name)
         })
+        .on("commands", commands)
+        .set_check("commands", owner_check)
         .on("ping", ping_command)
         .set_check("ping", owner_check) // Ensure only the owner can run this
         .on("emoji cat", cat_command)
@@ -84,12 +109,27 @@ fn main() {
 // This may bring more features available for commands in the future. See the
 // "multiply" command below for some of the power that the `command!` macro can
 // bring.
-command!(cat_command(context, _msg, _arg) {
+command!(cat_command(context, _msg, _args) {
     if let Err(why) = context.say(":cat:") {
         println!("Eror sending message: {:?}", why);
     }
 });
 
+command!(commands(context, _msg, _args) {
+    let mut contents = "Commands used:\n".to_owned();
+
+    let data = context.data.lock().unwrap();
+    let counter = data.get::<CommandCounter>().unwrap();
+
+    for (k, v) in counter {
+        let _ = write!(contents, "- {name}: {amount}\n", name=k, amount=v);
+    }
+
+    if let Err(why) = context.say(&contents) {
+        println!("Error sending message: {:?}", why);
+    }
+});
+
 fn dog_command(context: &Context, _msg: &Message, _args: Vec<String>) {
     if let Err(why) = context.say(":dog:") {
         println!("Error sending message: {:?}", why);
diff --git a/src/client/context.rs b/src/client/context.rs
index 4fca519..af90447 100644
--- a/src/client/context.rs
+++ b/src/client/context.rs
@@ -6,6 +6,7 @@ use std::sync::{Arc, Mutex};
 use super::gateway::Shard;
 use super::rest::{self, GuildPagination};
 use super::login_type::LoginType;
+use typemap::ShareMap;
 use ::utils::builder::{
     CreateEmbed,
     CreateInvite,
@@ -82,6 +83,11 @@ pub struct Context {
     ///
     /// [`on_message`]: struct.Client.html#method.on_message
     pub channel_id: Option<ChannelId>,
+    /// A clone of [`Client::data`]. Refer to its documentation for more
+    /// information.
+    ///
+    /// [`Client::data`]: struct.Client.html#method.data
+    pub data: Arc<Mutex<ShareMap>>,
     /// The associated shard which dispatched the event handler.
     ///
     /// Note that if you are sharding, in relevant terms, this is the shard
@@ -101,9 +107,11 @@ impl Context {
     #[doc(hidden)]
     pub fn new(channel_id: Option<ChannelId>,
                shard: Arc<Mutex<Shard>>,
+               data: Arc<Mutex<ShareMap>>,
                login_type: LoginType) -> Context {
         Context {
             channel_id: channel_id,
+            data: data,
             shard: shard,
             login_type: login_type,
         }
diff --git a/src/client/dispatch.rs b/src/client/dispatch.rs
index 44832cc..3207a0a 100644
--- a/src/client/dispatch.rs
+++ b/src/client/dispatch.rs
@@ -4,6 +4,7 @@ use super::event_store::EventStore;
 use super::login_type::LoginType;
 use super::Context;
 use super::gateway::Shard;
+use typemap::ShareMap;
 use ::model::event::Event;
 use ::model::{ChannelId, Message};
 
@@ -38,20 +39,23 @@ macro_rules! update {
 
 fn context(channel_id: Option<ChannelId>,
            conn: Arc<Mutex<Shard>>,
+           data: Arc<Mutex<ShareMap>>,
            login_type: LoginType) -> Context {
-    Context::new(channel_id, conn, login_type)
+    Context::new(channel_id, conn, data, login_type)
 }
 
 #[cfg(feature="framework")]
 pub fn dispatch(event: Event,
                 conn: Arc<Mutex<Shard>>,
                 framework: Arc<Mutex<Framework>>,
+                data: Arc<Mutex<ShareMap>>,
                 login_type: LoginType,
                 event_store: Arc<RwLock<EventStore>>) {
     match event {
         Event::MessageCreate(event) => {
             let context = context(Some(event.message.channel_id),
                                   conn,
+                                  data,
                                   login_type);
             let mut framework = framework.lock().expect("framework poisoned");
 
@@ -65,7 +69,7 @@ pub fn dispatch(event: Event,
                 dispatch_message(context, event.message, event_store);
             }
         },
-        other => handle_event(other, conn, login_type, event_store),
+        other => handle_event(other, conn, data, login_type, event_store),
     }
 }
 
@@ -73,17 +77,19 @@ pub fn dispatch(event: Event,
 pub fn dispatch(event: Event,
                 conn: Arc<Mutex<Shard>>,
                 login_type: LoginType,
+                data: Arc<Mutex<ShareMap>>,
                 event_store: Arc<RwLock<EventStore>>) {
     match event {
         Event::MessageCreate(event) => {
             let context = context(Some(event.message.channel_id),
                                   conn,
+                                  data,
                                   login_type);
             dispatch_message(context.clone(),
                              event.message.clone(),
                              event_store);
         },
-        other => handle_event(other, conn, login_type, event_store),
+        other => handle_event(other, conn, data, login_type, event_store),
     }
 }
 
@@ -102,6 +108,7 @@ fn dispatch_message(context: Context,
 #[allow(cyclomatic_complexity)]
 fn handle_event(event: Event,
                 conn: Arc<Mutex<Shard>>,
+                data: Arc<Mutex<ShareMap>>,
                 login_type: LoginType,
                 event_store: Arc<RwLock<EventStore>>) {
     match event {
@@ -109,7 +116,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_call_create, event_store) {
                 update!(update_with_call_create, event);
 
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -121,7 +128,7 @@ fn handle_event(event: Event,
         },
         Event::CallDelete(event) => {
             if let Some(ref handler) = handler!(on_call_delete, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -141,7 +148,7 @@ fn handle_event(event: Event,
         },
         Event::CallUpdate(event) => {
             if let Some(ref handler) = handler!(on_call_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -172,6 +179,7 @@ fn handle_event(event: Event,
                 update!(update_with_channel_create, event);
                 let context = context(Some(event.channel.id()),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -185,7 +193,7 @@ fn handle_event(event: Event,
         Event::ChannelDelete(event) => {
             if let Some(ref handler) = handler!(on_channel_delete, event_store) {
                 update!(update_with_channel_delete, event);
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -199,6 +207,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_channel_pins_ack, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -211,6 +220,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_channel_pins_update, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -225,6 +235,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_channel_recipient_addition, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -239,6 +250,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_channel_recipient_removal, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -251,6 +263,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_channel_update, event_store) {
                 let context = context(Some(event.channel.id()),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -275,7 +288,7 @@ fn handle_event(event: Event,
         },
         Event::FriendSuggestionCreate(event) => {
             if let Some(ref handler) = handler!(on_friend_suggestion_create, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -285,7 +298,7 @@ fn handle_event(event: Event,
         },
         Event::FriendSuggestionDelete(event) => {
             if let Some(ref handler) = handler!(on_friend_suggestion_delete, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -295,7 +308,7 @@ fn handle_event(event: Event,
         },
         Event::GuildBanAdd(event) => {
             if let Some(ref handler) = handler!(on_guild_ban_addition, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -305,7 +318,7 @@ fn handle_event(event: Event,
         },
         Event::GuildBanRemove(event) => {
             if let Some(ref handler) = handler!(on_guild_ban_removal, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -317,7 +330,7 @@ fn handle_event(event: Event,
             update!(update_with_guild_create, event);
 
             if let Some(ref handler) = handler!(on_guild_create, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -327,7 +340,7 @@ fn handle_event(event: Event,
         },
         Event::GuildDelete(event) => {
             if let Some(ref handler) = handler!(on_guild_delete, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -351,7 +364,7 @@ fn handle_event(event: Event,
             update!(update_with_guild_emojis_update, event);
 
             if let Some(ref handler) = handler!(on_guild_emojis_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -361,7 +374,7 @@ fn handle_event(event: Event,
         },
         Event::GuildIntegrationsUpdate(event) => {
             if let Some(ref handler) = handler!(on_guild_integrations_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -373,7 +386,7 @@ fn handle_event(event: Event,
             update!(update_with_guild_member_add, event);
 
             if let Some(ref handler) = handler!(on_guild_member_addition, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -383,7 +396,7 @@ fn handle_event(event: Event,
         },
         Event::GuildMemberRemove(event) => {
             if let Some(ref handler) = handler!(on_guild_member_removal, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -405,7 +418,7 @@ fn handle_event(event: Event,
         },
         Event::GuildMemberUpdate(event) => {
             if let Some(ref handler) = handler!(on_guild_member_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -436,7 +449,7 @@ fn handle_event(event: Event,
             update!(update_with_guild_members_chunk, event);
 
             if let Some(ref handler) = handler!(on_guild_members_chunk, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -448,7 +461,7 @@ fn handle_event(event: Event,
             update!(update_with_guild_role_create, event);
 
             if let Some(ref handler) = handler!(on_guild_role_create, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -458,7 +471,7 @@ fn handle_event(event: Event,
         },
         Event::GuildRoleDelete(event) => {
             if let Some(ref handler) = handler!(on_guild_role_delete, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -480,7 +493,7 @@ fn handle_event(event: Event,
         },
         Event::GuildRoleUpdate(event) => {
             if let Some(ref handler) = handler!(on_guild_role_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -502,7 +515,7 @@ fn handle_event(event: Event,
         },
         Event::GuildSync(event) => {
             if let Some(ref handler) = handler!(on_guild_sync, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -514,7 +527,7 @@ fn handle_event(event: Event,
             update!(update_with_guild_unavailable, event);
 
             if let Some(ref handler) = handler!(on_guild_unavailable, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -524,7 +537,7 @@ fn handle_event(event: Event,
         },
         Event::GuildUpdate(event) => {
             if let Some(ref handler) = handler!(on_guild_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -551,6 +564,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_message_ack, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -565,6 +579,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_message_delete_bulk, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -577,6 +592,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_message_delete, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -589,6 +605,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_message_update, event_store) {
                 let context = context(Some(event.channel_id),
                                            conn,
+                                           data,
                                            login_type);
                 let handler = handler.clone();
 
@@ -601,7 +618,7 @@ fn handle_event(event: Event,
             update!(update_with_presences_replace, event);
 
             if let Some(handler) = handler!(on_presence_replace, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -613,7 +630,7 @@ fn handle_event(event: Event,
             update!(update_with_presence_update, event);
 
             if let Some(handler) = handler!(on_presence_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -625,6 +642,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_reaction_add, event_store) {
                 let context = context(Some(event.reaction.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -637,6 +655,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_reaction_remove, event_store) {
                 let context = context(Some(event.reaction.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -649,6 +668,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_reaction_remove_all, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -661,7 +681,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_ready, event_store) {
                 update!(update_with_ready, event);
 
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -675,7 +695,7 @@ fn handle_event(event: Event,
             update!(update_with_relationship_add, event);
 
             if let Some(ref handler) = handler!(on_relationship_addition, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -687,7 +707,7 @@ fn handle_event(event: Event,
             update!(update_with_relationship_remove, event);
 
             if let Some(ref handler) = handler!(on_relationship_removal, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -697,7 +717,7 @@ fn handle_event(event: Event,
         },
         Event::Resumed(event) => {
             if let Some(ref handler) = handler!(on_resume, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -709,6 +729,7 @@ fn handle_event(event: Event,
             if let Some(ref handler) = handler!(on_typing_start, event_store) {
                 let context = context(Some(event.channel_id),
                                       conn,
+                                      data,
                                       login_type);
                 let handler = handler.clone();
 
@@ -719,7 +740,7 @@ fn handle_event(event: Event,
         },
         Event::Unknown(event) => {
             if let Some(ref handler) = handler!(on_unknown, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -729,7 +750,7 @@ fn handle_event(event: Event,
         },
         Event::UserGuildSettingsUpdate(event) => {
             if let Some(ref handler) = handler!(on_user_guild_settings_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -751,7 +772,7 @@ fn handle_event(event: Event,
         },
         Event::UserNoteUpdate(event) => {
             if let Some(ref handler) = handler!(on_note_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -773,7 +794,7 @@ fn handle_event(event: Event,
         },
         Event::UserSettingsUpdate(event) => {
             if let Some(ref handler) = handler!(on_user_settings_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -796,7 +817,7 @@ fn handle_event(event: Event,
         },
         Event::UserUpdate(event) => {
             if let Some(ref handler) = handler!(on_user_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 feature_cache! {{
@@ -818,7 +839,7 @@ fn handle_event(event: Event,
         },
         Event::VoiceServerUpdate(event) => {
             if let Some(ref handler) = handler!(on_voice_server_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -830,7 +851,7 @@ fn handle_event(event: Event,
             update!(update_with_voice_state_update, event);
 
             if let Some(ref handler) = handler!(on_voice_state_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
@@ -840,7 +861,7 @@ fn handle_event(event: Event,
         },
         Event::WebhookUpdate(event) => {
             if let Some(ref handler) = handler!(on_webhook_update, event_store) {
-                let context = context(None, conn, login_type);
+                let context = context(None, conn, data, login_type);
                 let handler = handler.clone();
 
                 thread::spawn(move || {
diff --git a/src/client/mod.rs b/src/client/mod.rs
index 0369677..cf67b5b 100644
--- a/src/client/mod.rs
+++ b/src/client/mod.rs
@@ -42,6 +42,7 @@ use std::collections::{BTreeMap, HashMap};
 use std::sync::{Arc, Mutex, RwLock};
 use std::thread;
 use std::time::Duration;
+use typemap::ShareMap;
 use websocket::client::Receiver;
 use websocket::stream::WebSocketStream;
 use ::internal::prelude::{Error, Result, Value};
@@ -150,6 +151,23 @@ lazy_static! {
 /// [`Event::MessageCreate`]: ../model/event/enum.Event.html#variant.MessageCreate
 /// [sharding docs]: gateway/index.html#sharding
 pub struct Client {
+    /// A ShareMap which requires types to be Send + Sync. This is a map that
+    /// can be safely shared across contexts.
+    ///
+    /// The purpose of the data field is to be accessible and persistent across
+    /// contexts; that is, data can be modified by one context, and will persist
+    /// through the future and be accessible through other contexts. This is
+    /// useful for anything that should "live" through the program: counters,
+    /// database connections, custom user caches, etc.
+    ///
+    /// In the meaning of a context, this data can be accessed through
+    /// [`Context::data`].
+    ///
+    /// Refer to [example 06] for an example on using the `data` field.
+    ///
+    /// [`Context::data`]: struct.Context.html#method.data
+    /// [example 06]: https://github.com/zeyla/serenity.rs/tree/master/examples/06_command_framework
+    pub data: Arc<Mutex<ShareMap>>,
     /// A vector of all active shards that have received their [`Event::Ready`]
     /// payload, and have dispatched to [`on_ready`] if an event handler was
     /// configured.
@@ -773,18 +791,21 @@ impl Client {
                                 dispatch(Event::Ready(ready),
                                          shard.clone(),
                                          self.framework.clone(),
+                                         self.data.clone(),
                                          self.login_type,
                                          self.event_store.clone());
                             } else {
                                 dispatch(Event::Ready(ready),
                                          shard.clone(),
+                                         self.data.clone(),
                                          self.login_type,
                                          self.event_store.clone());
                             }}
 
-                            let shard_clone = shard.clone();
+                            let data_clone = self.data.clone();
                             let event_store = self.event_store.clone();
                             let login_type = self.login_type;
+                            let shard_clone = shard.clone();
 
                             feature_framework! {{
                                 let framework = self.framework.clone();
@@ -792,6 +813,7 @@ impl Client {
                                 thread::spawn(move || {
                                     handle_shard(shard_clone,
                                                  framework,
+                                                 data_clone,
                                                  login_type,
                                                  event_store,
                                                  receiver)
@@ -799,6 +821,7 @@ impl Client {
                             } else {
                                 thread::spawn(move || {
                                     handle_shard(shard_clone,
+                                                 data_clone,
                                                  login_type,
                                                  event_store,
                                                  receiver)
@@ -1125,6 +1148,7 @@ impl Client {
 #[cfg(feature="framework")]
 fn handle_shard(shard: Arc<Mutex<Shard>>,
                 framework: Arc<Mutex<Framework>>,
+                data: Arc<Mutex<ShareMap>>,
                 login_type: LoginType,
                 event_store: Arc<RwLock<EventStore>>,
                 mut receiver: Receiver<WebSocketStream>) {
@@ -1146,6 +1170,7 @@ fn handle_shard(shard: Arc<Mutex<Shard>>,
         dispatch(event,
                  shard.clone(),
                  framework.clone(),
+                 data.clone(),
                  login_type,
                  event_store.clone());
     }
@@ -1153,6 +1178,7 @@ fn handle_shard(shard: Arc<Mutex<Shard>>,
 
 #[cfg(not(feature="framework"))]
 fn handle_shard(shard: Arc<Mutex<Shard>>,
+                data: Arc<Mutex<ShareMap>>,
                 login_type: LoginType,
                 event_store: Arc<RwLock<EventStore>>,
                 mut receiver: Receiver<WebSocketStream>) {
@@ -1173,6 +1199,7 @@ fn handle_shard(shard: Arc<Mutex<Shard>>,
 
         dispatch(event,
                  shard.clone(),
+                 data.clone(),
                  login_type,
                  event_store.clone());
     }
@@ -1185,17 +1212,19 @@ fn login(token: &str, login_type: LoginType) -> Client {
 
     feature_framework! {{
         Client {
-            shards: Vec::default(),
+            data: Arc::new(Mutex::new(ShareMap::custom())),
             event_store: Arc::new(RwLock::new(EventStore::default())),
             framework: Arc::new(Mutex::new(Framework::default())),
             login_type: login_type,
+            shards: Vec::default(),
             token: token.to_owned(),
         }
     } else {
         Client {
-            shards: Vec::default(),
+            data: Arc::new(Mutex::new(ShareMap::custom())),
             event_store: Arc::new(RwLock::new(EventStore::default())),
             login_type: login_type,
+            shards: Vec::default(),
             token: token.to_owned(),
         }
     }}
diff --git a/src/lib.rs b/src/lib.rs
index ca4a2fe..29237da 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -145,6 +145,7 @@ extern crate hyper;
 extern crate multipart;
 extern crate serde_json;
 extern crate time;
+extern crate typemap;
 extern crate websocket;
 
 #[cfg(feature="voice")]