✨ add automatic typed json ser/de operations

Cargo.toml

@@ -12,6 +12,7 @@ edition = "2018"
 [features]
 default = ["tls"]
 tls = ["openssl"]
+json = ["dep:serde", "dep:serde_json"]
 
 [dependencies]
 byteorder = "1"
@@ -20,3 +21,5 @@ rand = "0.8"
 enum_dispatch = "0.3"
 openssl = { version = "^0.10", optional = true }
 r2d2 = "^0.8"
+serde = { version = "1.0.197", optional = true , features = ["derive"] }
+serde_json = { version = "1.0.115", optional = true }

README.md

@@ -33,7 +33,8 @@ memcache = "*"
 - [ ] Encodings
   - [x] Typed interface
   - [ ] Automatically compress
-  - [ ] Automatically serialize to JSON / msgpack etc
+  - [x] Automatically serialize to JSON
+  - [ ] Automatically serialize to msgpack
 - [x] Memcached cluster support with custom key hash algorithm
 - [x] Authority
   - [x] Binary protocol (plain SASL authority plain)

src/client.rs

@@ -12,6 +12,9 @@ use crate::stream::Stream;
 use crate::value::{FromMemcacheValueExt, ToMemcacheValue};
 use r2d2::Pool;
 
+#[cfg(feature = "json")]
+use serde::{Deserialize, Serialize};
+
 pub type Stats = HashMap<String, String>;
 
 pub trait Connectable {
@@ -266,6 +269,47 @@ impl Client {
         return Ok(result);
     }
 
+    /// Get a key from memcached server and deserialize it as JSON. This function is only available when the `json` feature is enabled.
+    /// The value type should implement `FromMemcacheValueExt` and `serde::Deserialize`.
+    ///
+    /// Example:
+    /// ```rust
+    /// use serde::{Serialize, Deserialize};
+    ///
+    /// #[derive(Debug, Serialize, Deserialize)]
+    /// struct MyStruct {
+    ///     value: String,
+    ///     number: i32,
+    ///     flag: bool,
+    ///     array: Vec<i32>,
+    /// }
+    ///
+    /// let client = memcache::Client::connect("memcache://localhost:12345").unwrap();
+    /// let value = MyStruct {
+    ///     value: "hello".to_string(),
+    ///     number: 42,
+    ///     flag: true,
+    ///     array: vec![1, 2, 3],
+    /// };
+    /// client.set_json("foo", value, 10).unwrap();
+    /// let result: MyStruct = client.get_json("foo").unwrap().unwrap();
+    ///
+    /// assert_eq!(result.value, "hello");
+    /// assert_eq!(result.number, 42);
+    /// assert_eq!(result.flag, true);
+    /// assert_eq!(result.array, vec![1, 2, 3]);
+    /// ```
+    #[cfg(feature = "json")]
+    pub fn get_json<V: for<'a> Deserialize<'a>>(&self, key: &str) -> Result<Option<V>, MemcacheError> {
+        let value: Option<String> = self.get(key)?;
+        let value = match value {
+            Some(value) => value,
+            None => return Ok(None),
+        };
+
+        return serde_json::from_str(&value).map_err(|e| MemcacheError::JsonError(e));
+    }
+
     /// Set a key with associate value into memcached server with expiration seconds.
     ///
     /// Example:
@@ -280,6 +324,32 @@ impl Client {
         return self.get_connection(key).get()?.set(key, value, expiration);
     }
 
+    /// Set a key with associate value into memcached server with expiration seconds. The value will be serialized as JSON. This function is only available when the `json` feature is enabled.
+    ///
+    /// Example:
+    /// ```rust
+    /// use serde::Serialize;
+    ///
+    /// #[derive(Serialize)]
+    /// struct MyStruct {
+    ///     value: String,
+    ///     number: i32,
+    /// }
+    ///
+    /// let client = memcache::Client::connect("memcache://localhost:12345").unwrap();
+    /// let value = MyStruct {
+    ///     value: "hello".to_string(),
+    ///     number: 42,
+    /// };
+    /// client.set_json("foo", value, 10).unwrap();
+    /// client.flush().unwrap();
+    /// ```
+    #[cfg(feature = "json")]
+    pub fn set_json<V: Serialize>(&self, key: &str, value: V, expiration: u32) -> Result<(), MemcacheError> {
+        let value = serde_json::to_string(&value).map_err(|e| MemcacheError::JsonError(e))?;
+        return self.set(key, value, expiration);
+    }
+
     /// Compare and swap a key with the associate value into memcached server with expiration seconds.
     /// `cas_id` should be obtained from a previous `gets` call.
     ///

src/error.rs

@@ -1,4 +1,4 @@
 use r2d2;
 use std::borrow::Cow;
 use std::error;
 use std::fmt;
@@ -6,7 +6,7 @@
 use std::num;
 use std::str;
 use std::string;
 use url;
 
 /// Client-side errors
 #[derive(Debug, PartialEq)]
@@ -239,6 +239,9 @@
     ParseError(ParseError),
     /// ConnectionPool errors
     PoolError(r2d2::Error),
+    /// Json errors (only available with `json` feature) for invalid json strings
+    #[cfg(feature = "json")]
+    JsonError(serde_json::Error),
 }
 
 impl fmt::Display for MemcacheError {
@@ -253,6 +256,8 @@
             MemcacheError::ServerError(ref err) => err.fmt(f),
             MemcacheError::CommandError(ref err) => err.fmt(f),
             MemcacheError::PoolError(ref err) => err.fmt(f),
+            #[cfg(feature = "json")]
+            MemcacheError::JsonError(ref err) => err.fmt(f),
         }
     }
 }
@@ -269,6 +274,8 @@
             MemcacheError::ServerError(_) => None,
             MemcacheError::CommandError(_) => None,
             MemcacheError::PoolError(ref p) => p.source(),
+            #[cfg(feature = "json")]
+            MemcacheError::JsonError(ref e) => e.source(),
         }
     }
 }