1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553
use std::{fmt, io};
use crate::connection::ConnectionLike;
use crate::pipeline::Pipeline;
use crate::types::{from_redis_value, FromRedisValue, RedisResult, RedisWrite, ToRedisArgs};
/// An argument to a redis command
#[derive(Clone)]
pub enum Arg<D> {
/// A normal argument
Simple(D),
/// A cursor argument created from `cursor_arg()`
Cursor,
}
/// Represents redis commands.
#[derive(Clone)]
pub struct Cmd {
data: Vec<u8>,
// Arg::Simple contains the offset that marks the end of the argument
args: Vec<Arg<usize>>,
cursor: Option<u64>,
}
/// Represents a redis iterator.
pub struct Iter<'a, T: FromRedisValue> {
batch: std::vec::IntoIter<T>,
cursor: u64,
con: &'a mut (dyn 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 {
if let Some(v) = self.batch.next() {
return Some(v);
};
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, batch): (u64, Vec<T>) = unwrap_or!(from_redis_value(&rv).ok(), return None);
self.cursor = cur;
self.batch = batch.into_iter();
}
}
}
#[cfg(feature = "aio")]
use crate::aio::ConnectionLike as AsyncConnection;
/// Represents a redis iterator that can be used with async connections.
#[cfg(feature = "aio")]
pub struct AsyncIter<'a, T: FromRedisValue + 'a> {
batch: std::vec::IntoIter<T>,
con: &'a mut (dyn AsyncConnection + Send + 'a),
cmd: Cmd,
}
#[cfg(feature = "aio")]
impl<'a, T: FromRedisValue + 'a> AsyncIter<'a, T> {
/// ```rust,no_run
/// # use redis::AsyncCommands;
/// # async fn scan_set() -> redis::RedisResult<()> {
/// # let client = redis::Client::open("redis://127.0.0.1/")?;
/// # let mut con = client.get_async_connection().await?;
/// con.sadd("my_set", 42i32).await?;
/// con.sadd("my_set", 43i32).await?;
/// let mut iter: redis::AsyncIter<i32> = con.sscan("my_set").await?;
/// while let Some(element) = iter.next_item().await {
/// assert!(element == 42 || element == 43);
/// }
/// # Ok(())
/// # }
/// ```
#[inline]
pub async fn next_item(&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 {
if let Some(v) = self.batch.next() {
return Some(v);
};
if let Some(cursor) = self.cmd.cursor {
if cursor == 0 {
return None;
}
} else {
return None;
}
let rv = unwrap_or!(
self.con.req_packed_command(&self.cmd).await.ok(),
return None
);
let (cur, batch): (u64, Vec<T>) = unwrap_or!(from_redis_value(&rv).ok(), return None);
self.cmd.cursor = Some(cur);
self.batch = batch.into_iter();
}
}
}
fn countdigits(mut v: usize) -> usize {
let mut result = 1;
loop {
if v < 10 {
return result;
}
if v < 100 {
return result + 1;
}
if v < 1000 {
return result + 2;
}
if v < 10000 {
return result + 3;
}
v /= 10000;
result += 4;
}
}
#[inline]
fn bulklen(len: usize) -> usize {
1 + countdigits(len) + 2 + len + 2
}
fn args_len<'a, I>(args: I, cursor: u64) -> usize
where
I: IntoIterator<Item = Arg<&'a [u8]>> + ExactSizeIterator,
{
let mut totlen = 1 + countdigits(args.len()) + 2;
for item in args {
totlen += bulklen(match item {
Arg::Cursor => countdigits(cursor as usize),
Arg::Simple(val) => val.len(),
});
}
totlen
}
pub(crate) fn cmd_len(cmd: &Cmd) -> usize {
args_len(cmd.args_iter(), cmd.cursor.unwrap_or(0))
}
fn encode_command<'a, I>(args: I, cursor: u64) -> Vec<u8>
where
I: IntoIterator<Item = Arg<&'a [u8]>> + Clone + ExactSizeIterator,
{
let mut cmd = Vec::new();
write_command_to_vec(&mut cmd, args, cursor);
cmd
}
fn write_command_to_vec<'a, I>(cmd: &mut Vec<u8>, args: I, cursor: u64)
where
I: IntoIterator<Item = Arg<&'a [u8]>> + Clone + ExactSizeIterator,
{
let totlen = args_len(args.clone(), cursor);
cmd.reserve(totlen);
write_command(cmd, args, cursor).unwrap()
}
fn write_command<'a, I>(cmd: &mut (impl ?Sized + io::Write), args: I, cursor: u64) -> io::Result<()>
where
I: IntoIterator<Item = Arg<&'a [u8]>> + Clone + ExactSizeIterator,
{
cmd.write_all(b"*")?;
::itoa::write(&mut *cmd, args.len())?;
cmd.write_all(b"\r\n")?;
let mut cursor_bytes = itoa::Buffer::new();
for item in args {
let bytes = match item {
Arg::Cursor => cursor_bytes.format(cursor).as_bytes(),
Arg::Simple(val) => val,
};
cmd.write_all(b"$")?;
::itoa::write(&mut *cmd, bytes.len())?;
cmd.write_all(b"\r\n")?;
cmd.write_all(bytes)?;
cmd.write_all(b"\r\n")?;
}
Ok(())
}
impl RedisWrite for Cmd {
fn write_arg(&mut self, arg: &[u8]) {
self.data.extend_from_slice(arg);
self.args.push(Arg::Simple(self.data.len()));
}
fn write_arg_fmt(&mut self, arg: impl fmt::Display) {
use std::io::Write;
write!(self.data, "{}", arg).unwrap();
self.args.push(Arg::Simple(self.data.len()));
}
}
impl Default for Cmd {
fn default() -> Cmd {
Cmd::new()
}
}
/// 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 mut con = client.get_connection().unwrap();
/// let mut cmd = redis::cmd("SMEMBERS");
/// let mut iter : redis::Iter<i32> = cmd.arg("my_set").clone().iter(&mut con).unwrap();
/// ```
impl Cmd {
/// Creates a new empty command.
pub fn new() -> Cmd {
Cmd {
data: vec![],
args: vec![],
cursor: None,
}
}
/// 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 mut 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 {
arg.write_redis_args(self);
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 mut con = client.get_connection().unwrap();
/// let mut cmd = redis::cmd("SSCAN");
/// let mut iter : redis::Iter<isize> =
/// cmd.arg("my_set").cursor_arg(0).clone().iter(&mut 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> {
let mut cmd = Vec::new();
self.write_packed_command(&mut cmd);
cmd
}
pub(crate) fn write_packed_command(&self, cmd: &mut Vec<u8>) {
write_command_to_vec(cmd, self.args_iter(), self.cursor.unwrap_or(0))
}
pub(crate) fn write_packed_command_preallocated(&self, cmd: &mut Vec<u8>) {
write_command(cmd, self.args_iter(), self.cursor.unwrap_or(0)).unwrap()
}
/// 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_iter(), 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: &mut dyn ConnectionLike) -> RedisResult<T> {
match con.req_command(self) {
Ok(val) => from_redis_value(&val),
Err(e) => Err(e),
}
}
/// Async version of `query`.
#[inline]
#[cfg(feature = "aio")]
pub async fn query_async<C, T: FromRedisValue>(&self, con: &mut C) -> RedisResult<T>
where
C: crate::aio::ConnectionLike,
{
let val = con.req_packed_command(self).await?;
from_redis_value(&val)
}
/// 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<T: FromRedisValue>(self, con: &mut dyn ConnectionLike) -> RedisResult<Iter<'_, T>> {
let rv = con.req_command(&self)?;
let (cursor, batch) = if rv.looks_like_cursor() {
from_redis_value::<(u64, Vec<T>)>(&rv)?
} else {
(0, from_redis_value(&rv)?)
};
Ok(Iter {
batch: batch.into_iter(),
cursor,
con,
cmd: self,
})
}
/// Similar to `iter()` but returns an AsyncIter over the items of the
/// bulk result or iterator. A [futures::Stream](https://docs.rs/futures/0.3.3/futures/stream/trait.Stream.html)
/// can be obtained by calling `stream()` on the AsyncIter. 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 stream will query for more
/// items until the server side cursor is exhausted.
///
/// This is useful for commands such as `SSCAN`, `SCAN` and others in async contexts.
///
/// 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).
#[cfg(feature = "aio")]
#[inline]
pub async fn iter_async<'a, T: FromRedisValue + 'a>(
mut self,
con: &'a mut (dyn AsyncConnection + Send),
) -> RedisResult<AsyncIter<'a, T>> {
let rv = con.req_packed_command(&self).await?;
let (cursor, batch) = if rv.looks_like_cursor() {
from_redis_value::<(u64, Vec<T>)>(&rv)?
} else {
(0, from_redis_value(&rv)?)
};
if cursor == 0 {
self.cursor = None;
} else {
self.cursor = Some(cursor);
}
Ok(AsyncIter {
batch: batch.into_iter(),
con,
cmd: self,
})
}
/// 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 mut con = client.get_connection().unwrap();
/// let _ : () = redis::cmd("PING").query(&mut con).unwrap();
/// ```
#[inline]
pub fn execute(&self, con: &mut dyn ConnectionLike) {
self.query::<()>(con).unwrap();
}
/// Returns an iterator over the arguments in this command (including the command name itself)
pub fn args_iter(&self) -> impl Iterator<Item = Arg<&[u8]>> + Clone + ExactSizeIterator {
let mut prev = 0;
self.args.iter().map(move |arg| match *arg {
Arg::Simple(i) => {
let arg = Arg::Simple(&self.data[prev..i]);
prev = i;
arg
}
Arg::Cursor => Arg::Cursor,
})
}
// Get a reference to the argument at `idx`
#[cfg(feature = "cluster")]
pub(crate) fn arg_idx(&self, idx: usize) -> Option<&[u8]> {
if idx >= self.args.len() {
return None;
}
let start = if idx == 0 {
0
} else {
match self.args[idx - 1] {
Arg::Simple(n) => n,
_ => 0,
}
};
let end = match self.args[idx] {
Arg::Simple(n) => n,
_ => 0,
};
if start == 0 && end == 0 {
return None;
}
Some(&self.data[start..end])
}
}
/// 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(name: &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
/// # use redis::ToRedisArgs;
/// let mut args = vec![];
/// args.extend("SET".to_redis_args());
/// args.extend("my_key".to_redis_args());
/// args.extend(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::Simple(&x[..])), 0)
}
/// Shortcut for creating a new pipeline.
pub fn pipe() -> Pipeline {
Pipeline::new()
}
#[cfg(test)]
#[cfg(feature = "cluster")]
mod tests {
use super::Cmd;
#[test]
fn test_cmd_arg_idx() {
let mut c = Cmd::new();
assert_eq!(c.arg_idx(0), None);
c.arg("SET");
assert_eq!(c.arg_idx(0), Some(&b"SET"[..]));
assert_eq!(c.arg_idx(1), None);
c.arg("foo").arg("42");
assert_eq!(c.arg_idx(1), Some(&b"foo"[..]));
assert_eq!(c.arg_idx(2), Some(&b"42"[..]));
assert_eq!(c.arg_idx(3), None);
assert_eq!(c.arg_idx(4), None);
}
}