Add support for str_len

Author: gkorland

src/lib.rs

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate redismodule;
 
-use redismodule::{Context, RedisResult, NextArg};
+use redismodule::{Context, RedisResult, NextArg, RedisValue};
 use redismodule::native_types::RedisType;
 
 mod redisjson;
@@ -15,7 +15,7 @@ fn json_set(ctx: &Context, args: Vec<String>) -> RedisResult {
     let mut args = args.into_iter().skip(1);
 
     let key = args.next_string()?;
-      let value = args.next_string()?;
+    let value = args.next_string()?;
 
     let key = ctx.open_key_writable(&key);
 
@@ -40,13 +40,28 @@ fn json_get(ctx: &Context, args: Vec<String>) -> RedisResult {
     let key = ctx.open_key_writable(&key);
 
     let value = match key.get_value::<RedisJSON>(&REDIS_JSON_TYPE)? {
-        Some(doc) => { doc.to_string(&path)?.into() }
+        Some(doc) => doc.to_string(&path)?.into(),
         None => ().into()
     };
 
     Ok(value)
 }
 
+fn json_strlen(ctx: &Context, args: Vec<String>) -> RedisResult {
+    let mut args = args.into_iter().skip(1);
+    let key = args.next_string()?;
+    let path = args.next_string()?;
+
+    let key = ctx.open_key_writable(&key);
+
+    let length = match key.get_value::<RedisJSON>(&REDIS_JSON_TYPE)? {
+        Some(doc) => RedisValue::Integer(doc.str_len(&path)? as i64),
+        None => ().into()
+    };
+
+    Ok(length)
+}
+
 //////////////////////////////////////////////////////
 
 redis_module! {
@@ -58,5 +73,6 @@ redis_module! {
     commands: [
         ["json.set", json_set, "write"],
         ["json.get", json_get, ""],
+        ["json.strlen", json_strlen, ""],
     ],
 }

src/redisjson.rs

@@ -52,16 +52,35 @@ impl RedisJSON {
     pub fn to_string(&self, path: &str) -> Result<String, Error> {
         eprintln!("Serializing back to JSON");
 
+        let s = match self.get_doc(path)? {
+            Some(doc) => serde_json::to_string(&doc)?,
+            None => String::new()
+        };
+
+        Ok(s)
+    }
+
+    pub fn str_len(&self, path: &str) -> Result<usize, Error> {
+        let s = match self.get_doc(path)? {
+            Some(doc) => {
+                if doc.is_string() {
+                    serde_json::to_string(&doc)?.len() - 2 // removes ""
+                } else {
+                    0 // the value is not a String
+                }
+            }
+            None => 0 // path not found
+        };
+        Ok(s)
+    }
+
+    pub fn get_doc(&self, path: &str) -> Result<Option<&Value>, Error> {
         // Create a JSONPath selector
         let selector = Selector::new(path).map_err(|e| Error {
             msg: format!("{}", e),
         })?;
 
-        let s = match selector.find(&self.data).next() {
-            Some(doc) => serde_json::to_string(&doc)?,
-            None => String::new()
-        };
-
-        return Ok(s)
+        Ok(selector.find(&self.data).next())
     }
+
 }