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use types::{ToRedisArgs, FromRedisValue, Value, RedisResult, ErrorKind, from_redis_value}; use connection::ConnectionLike; #[derive(Clone)] enum Arg<'a> { Simple(Vec<u8>), Cursor, Borrowed(&'a [u8]), } /// Represents redis commands. #[derive(Clone)] pub struct Cmd { args: Vec<Arg<'static>>, cursor: Option<u64>, is_ignored: bool, } /// Represents a redis command pipeline. pub struct Pipeline { commands: Vec<Cmd>, transaction_mode: bool, } /// Represents a redis iterator. pub struct Iter<'a, T: FromRedisValue> { batch: Vec<T>, cursor: u64, con: &'a (ConnectionLike + 'a), cmd: Cmd, } impl<'a, T: FromRedisValue> Iterator for Iter<'a, T> { type Item = T; #[inline] fn next(&mut self) -> Option<T> { // we need to do this in a loop until we produce at least one item // or we find the actual end of the iteration. This is necessary // because with filtering an iterator it is possible that a whole // chunk is not matching the pattern and thus yielding empty results. loop { match self.batch.pop() { Some(v) => { return Some(v); } None => {} }; if self.cursor == 0 { return None; } let pcmd = unwrap_or!(self.cmd.get_packed_command_with_cursor( self.cursor), return None); let rv = unwrap_or!(self.con.req_packed_command( &pcmd).ok(), return None); let (cur, mut batch) : (u64, Vec<T>) = unwrap_or!( from_redis_value(&rv).ok(), return None); batch.reverse(); self.cursor = cur; self.batch = batch; } } } fn encode_command(args: &Vec<Arg>, cursor: u64) -> Vec<u8> { let mut cmd = vec![]; cmd.extend(format!("*{}\r\n", args.len()).as_bytes().iter().cloned()); { let mut encode = |item: &[u8]| { cmd.extend(format!("${}\r\n", item.len()).as_bytes().iter().cloned()); cmd.extend(item.iter().cloned()); cmd.extend(b"\r\n".iter().cloned()); }; for item in args.iter() { match *item { Arg::Cursor => encode(cursor.to_string().as_bytes()), Arg::Simple(ref val) => encode(val), Arg::Borrowed(ptr) => encode(ptr), } } } cmd } fn encode_pipeline(cmds: &[Cmd], atomic: bool) -> Vec<u8> { let mut rv = vec![]; if atomic { rv.extend(cmd("MULTI").get_packed_command().into_iter()); } for cmd in cmds.iter() { rv.extend(cmd.get_packed_command().into_iter()); } if atomic { rv.extend(cmd("EXEC").get_packed_command().into_iter()); } rv } /// A command acts as a builder interface to creating encoded redis /// requests. This allows you to easiy assemble a packed command /// by chaining arguments together. /// /// Basic example: /// /// ```rust /// redis::Cmd::new().arg("SET").arg("my_key").arg(42); /// ``` /// /// There is also a helper function called `cmd` which makes it a /// tiny bit shorter: /// /// ```rust /// redis::cmd("SET").arg("my_key").arg(42); /// ``` /// /// Because currently rust's currently does not have an ideal system /// for lifetimes of temporaries, sometimes you need to hold on to /// the initially generated command: /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let mut cmd = redis::cmd("SMEMBERS"); /// let mut iter : redis::Iter<i32> = cmd.arg("my_set").iter(&con).unwrap(); /// ``` impl Cmd { /// Creates a new empty command. pub fn new() -> Cmd { Cmd { args: vec![], cursor: None, is_ignored: false } } /// Appends an argument to the command. The argument passed must /// be a type that implements `ToRedisArgs`. Most primitive types as /// well as vectors of primitive types implement it. /// /// For instance all of the following are valid: /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// redis::cmd("SET").arg(&["my_key", "my_value"]); /// redis::cmd("SET").arg("my_key").arg(42); /// redis::cmd("SET").arg("my_key").arg(b"my_value"); /// ``` #[inline] pub fn arg<T: ToRedisArgs>(&mut self, arg: T) -> &mut Cmd { for item in arg.to_redis_args().into_iter() { self.args.push(Arg::Simple(item)); } self } /// Works similar to `arg` but adds a cursor argument. This is always /// an integer and also flips the command implementation to support a /// different mode for the iterators where the iterator will ask for /// another batch of items when the local data is exhausted. /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let mut cmd = redis::cmd("SSCAN"); /// let mut iter : redis::Iter<isize> = cmd.arg("my_set").cursor_arg(0).iter(&con).unwrap(); /// for x in iter { /// // do something with the item /// } /// ``` #[inline] pub fn cursor_arg(&mut self, cursor: u64) -> &mut Cmd { assert!(!self.in_scan_mode()); self.cursor = Some(cursor); self.args.push(Arg::Cursor); self } /// Returns the packed command as a byte vector. #[inline] pub fn get_packed_command(&self) -> Vec<u8> { encode_command(&self.args, self.cursor.unwrap_or(0)) } /// Like `get_packed_command` but replaces the cursor with the /// provided value. If the command is not in scan mode, `None` /// is returned. #[inline] fn get_packed_command_with_cursor(&self, cursor: u64) -> Option<Vec<u8>> { if !self.in_scan_mode() { None } else { Some(encode_command(&self.args, cursor)) } } /// Returns true if the command is in scan mode. #[inline] pub fn in_scan_mode(&self) -> bool { self.cursor.is_some() } /// Sends the command as query to the connection and converts the /// result to the target redis value. This is the general way how /// you can retrieve data. #[inline] pub fn query<T: FromRedisValue>(&self, con: &ConnectionLike) -> RedisResult<T> { let pcmd = self.get_packed_command(); match con.req_packed_command(&pcmd) { Ok(val) => from_redis_value(&val), Err(e) => Err(e), } } /// Similar to `query()` but returns an iterator over the items of the /// bulk result or iterator. In normal mode this is not in any way more /// efficient than just querying into a `Vec<T>` as it's internally /// implemented as buffering into a vector. This however is useful when /// `cursor_arg` was used in which case the iterator will query for more /// items until the server side cursor is exhausted. /// /// This is useful for commands such as `SSCAN`, `SCAN` and others. /// /// One speciality of this function is that it will check if the response /// looks like a cursor or not and always just looks at the payload. /// This way you can use the function the same for responses in the /// format of `KEYS` (just a list) as well as `SSCAN` (which returns a /// tuple of cursor and list). #[inline] pub fn iter<'a, T: FromRedisValue>(&self, con: &'a ConnectionLike) -> RedisResult<Iter<'a, T>> { let pcmd = self.get_packed_command(); let rv = try!(con.req_packed_command(&pcmd)); let mut batch : Vec<T>; let mut cursor = 0; if rv.looks_like_cursor() { let (next, b) : (u64, Vec<T>) = try!(from_redis_value(&rv)); batch = b; cursor = next; } else { batch = try!(from_redis_value(&rv)); } batch.reverse(); Ok(Iter { batch: batch, cursor: cursor, con: con, cmd: self.clone(), }) } /// This is a shortcut to `query()` that does not return a value and /// will fail the task if the query fails because of an error. This is /// mainly useful in examples and for simple commands like setting /// keys. /// /// This is equivalent to a call of query like this: /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let _ : () = redis::cmd("PING").query(&con).unwrap(); /// ``` #[inline] pub fn execute(&self, con: &ConnectionLike) { let _ : () = self.query(con).unwrap(); } } /// A pipeline allows you to send multiple commands in one go to the /// redis server. API wise it's very similar to just using a command /// but it allows multiple commands to be chained and some features such /// as iteration are not available. /// /// Basic example: /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let ((k1, k2),) : ((i32, i32),) = redis::pipe() /// .cmd("SET").arg("key_1").arg(42).ignore() /// .cmd("SET").arg("key_2").arg(43).ignore() /// .cmd("MGET").arg(&["key_1", "key_2"]).query(&con).unwrap(); /// ``` /// /// As you can see with `cmd` you can start a new command. By default /// each command produces a value but for some you can ignore them by /// calling `ignore` on the command. That way it will be skipped in the /// return value which is useful for `SET` commands and others, which /// do not have a useful return value. impl Pipeline { /// Creates an empty pipeline. For consistency with the `cmd` /// api a `pipe` function is provided as alias. pub fn new() -> Pipeline { Pipeline { commands: vec![], transaction_mode: false } } /// Starts a new command. Functions such as `arg` then become /// available to add more arguments to that command. #[inline] pub fn cmd(&mut self, name: &str) -> &mut Pipeline { self.commands.push(cmd(name)); self } /// Adds a command to the pipeline. #[inline] pub fn add_command(&mut self, cmd: &Cmd) -> &mut Pipeline { self.commands.push(cmd.clone()); self } #[inline] fn get_last_command(&mut self) -> &mut Cmd { let idx = match self.commands.len() { 0 => panic!("No command on stack"), x => x - 1, }; &mut self.commands[idx] } /// Adds an argument to the last started command. This works similar /// to the `arg` method of the `Cmd` object. /// /// Note that this function fails the task if executed on an empty pipeline. #[inline] pub fn arg<T: ToRedisArgs>(&mut self, arg: T) -> &mut Pipeline { { let cmd = self.get_last_command(); cmd.arg(arg); } self } /// Instructs the pipeline to ignore the return value of this command. /// It will still be ensured that it is not an error, but any successful /// result is just thrown away. This makes result processing through /// tuples much easier because you do not need to handle all the items /// you do not care about. /// /// Note that this function fails the task if executed on an empty pipeline. #[inline] pub fn ignore(&mut self) -> &mut Pipeline { { let cmd = self.get_last_command(); cmd.is_ignored = true; } self } /// This enables atomic mode. In atomic mode the whole pipeline is /// enclosed in `MULTI`/`EXEC`. From the user's point of view nothing /// changes however. This is easier than using `MULTI`/`EXEC` yourself /// as the format does not change. /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let (k1, k2) : (i32, i32) = redis::pipe() /// .atomic() /// .cmd("GET").arg("key_1") /// .cmd("GET").arg("key_2").query(&con).unwrap(); /// ``` #[inline] pub fn atomic(&mut self) -> &mut Pipeline { self.transaction_mode = true; self } fn make_pipeline_results(&self, resp: Vec<Value>) -> Value { let mut rv = vec![]; for (idx, result) in resp.into_iter().enumerate() { if !self.commands[idx].is_ignored { rv.push(result); } } Value::Bulk(rv) } fn execute_pipelined(&self, con: &ConnectionLike) -> RedisResult<Value> { Ok(self.make_pipeline_results(try!(con.req_packed_commands( &encode_pipeline(&self.commands, false), 0, self.commands.len())))) } fn execute_transaction(&self, con: &ConnectionLike) -> RedisResult<Value> { let mut resp = try!(con.req_packed_commands( &encode_pipeline(&self.commands, true), self.commands.len() + 1, 1)); match resp.pop() { Some(Value::Nil) => Ok(Value::Nil), Some(Value::Bulk(items)) => Ok(self.make_pipeline_results(items)), _ => fail!((ErrorKind::ResponseError, "Invalid response when parsing multi response")) } } /// Executes the pipeline and fetches the return values. Since most /// pipelines return different types it's recommended to use tuple /// matching to process the results: /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let (k1, k2) : (i32, i32) = redis::pipe() /// .cmd("SET").arg("key_1").arg(42).ignore() /// .cmd("SET").arg("key_2").arg(43).ignore() /// .cmd("GET").arg("key_1") /// .cmd("GET").arg("key_2").query(&con).unwrap(); /// ``` #[inline] pub fn query<T: FromRedisValue>(&self, con: &ConnectionLike) -> RedisResult<T> { from_redis_value(&( if self.commands.len() == 0 { Value::Bulk(vec![]) } else if self.transaction_mode { try!(self.execute_transaction(con)) } else { try!(self.execute_pipelined(con)) } )) } /// This is a shortcut to `query()` that does not return a value and /// will fail the task if the query of the pipeline fails. /// /// This is equivalent to a call of query like this: /// /// ```rust,no_run /// # let client = redis::Client::open("redis://127.0.0.1/").unwrap(); /// # let con = client.get_connection().unwrap(); /// let _ : () = redis::pipe().cmd("PING").query(&con).unwrap(); /// ``` #[inline] pub fn execute(&self, con: &ConnectionLike) { let _ : () = self.query(con).unwrap(); } } /// Shortcut function to creating a command with a single argument. /// /// The first argument of a redis command is always the name of the command /// which needs to be a string. This is the recommended way to start a /// command pipe. /// /// ```rust /// redis::cmd("PING"); /// ``` pub fn cmd<'a>(name: &'a str) -> Cmd { let mut rv = Cmd::new(); rv.arg(name); rv } /// Packs a bunch of commands into a request. This is generally a quite /// useless function as this functionality is nicely wrapped through the /// `Cmd` object, but in some cases it can be useful. The return value /// of this can then be send to the low level `ConnectionLike` methods. /// /// Example: /// /// ```rust,ignore /// # this is ignore because it uses unstable APIs. /// # use redis::ToRedisArgs; /// let mut args = vec![]; /// args.push_all(&"SET".to_redis_args()); /// args.push_all(&"my_key".to_redis_args()); /// args.push_all(&42.to_redis_args()); /// let cmd = redis::pack_command(&args); /// assert_eq!(cmd, b"*3\r\n$3\r\nSET\r\n$6\r\nmy_key\r\n$2\r\n42\r\n".to_vec()); /// ``` pub fn pack_command(args: &[Vec<u8>]) -> Vec<u8> { encode_command(&args.iter().map(|x| Arg::Borrowed(x)).collect(), 0) } /// Shortcut for creating a new pipeline. pub fn pipe() -> Pipeline { Pipeline::new() }