Implemented function to update an item

Cargo.lock

@@ -755,6 +755,12 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "either"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90e5c1c8368803113bf0c9584fc495a58b86dc8a29edbf8fe877d21d9507e797"
+
 [[package]]
 name = "embedded-hal"
 version = "0.2.7"
@@ -1361,6 +1367,15 @@ dependencies = [
  "waker-fn",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.3"
@@ -1554,6 +1569,7 @@ name = "mize"
 version = "0.1.0"
 dependencies = [
  "futures-util",
+ "itertools",
  "surrealdb",
  "tokio",
  "tokio-stream",

Cargo.toml

@@ -15,6 +15,7 @@ path = "src/client-main.rs"
 
 [dependencies]
 futures-util = "0.3.24"
+itertools = "0.10.5"
 surrealdb = "1.0.0-beta.7"
 tokio = {version = "1.21.0", features = ["full"]}
 tokio-stream = "0.1.9"

src/server/itemstore.rs

@@ -1,6 +1,7 @@
 
 use std::io;
 use surrealdb::Datastore;
+use itertools::Itertools;
 
 pub struct itemstore {
     db: surrealdb::Datastore,
@@ -66,6 +67,29 @@ impl itemstore {
     }
 
     pub async fn update(&self, id: u64, new_item: Item){
+        let mut tr = self.db.transaction(true, true).await.expect("creation of transaction failed");
+
+        let mut keys: Vec<String> = match tr.get(format!("{}", id).into_bytes()).await {
+            Ok(Some(val)) => decode(val),
+            Ok(None) => {
+                self.create(new_item);
+                tr.cancel();
+                return;
+            },
+            Err(e) => panic!("Error while querying the db: {}", e),
+        };
+
+        for field in new_item {
+            let key = format!("{}:{}", id, field[0]);
+            let val = field[1].clone();
+            keys.push(field[0].clone());
+            tr.set(key.into_bytes(), val.into_bytes()).await;
+        }
+
+        keys = keys.into_iter().unique().collect::<Vec<String>>();
+        tr.set(format!("{}", id).into_bytes(), encode(keys)).await;
+
+        tr.commit().await;
     }
 
     pub async fn delete(&self, id: u64){