From c58bf96a66ad491cce7f3009f378dfe75aea1901 Mon Sep 17 00:00:00 2001
From: Adrian <adrian.iosdev@gmail.com>
Date: Tue, 15 Aug 2023 10:54:28 +0300
Subject: [PATCH] Add key generator to use as extensions (#16)

* Add generator for shortened url

* Use shortener generator for POST endpoint
---
 Cargo.lock             | 14 ++++++++++++
 Cargo.toml             |  2 ++
 Tests/key_generator.rs |  8 +++++++
 src/key_generator.rs   |  9 ++++++++
 src/lib.rs             |  1 +
 src/routes/full_url.rs | 52 ++++++++++++++++++++++++++++++------------
 6 files changed, 71 insertions(+), 15 deletions(-)
 create mode 100644 Tests/key_generator.rs
 create mode 100644 src/key_generator.rs

diff --git a/Cargo.lock b/Cargo.lock
index 82dbf6b..87e2830 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -151,6 +151,12 @@ dependencies = [
  "rustc-demangle",
 ]
 
+[[package]]
+name = "base62"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f879ef8fc74665ed7f0e6127cb106315888fc2744f68e14b74f83edbb2a08992"
+
 [[package]]
 name = "base64"
 version = "0.13.1"
@@ -198,8 +204,10 @@ name = "briefly"
 version = "0.1.0"
 dependencies = [
  "axum",
+ "base62",
  "chrono",
  "config",
+ "md5",
  "reqwest",
  "serde",
  "sqlx",
@@ -970,6 +978,12 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "md5"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "490cc448043f947bae3cbee9c203358d62dbee0db12107a74be5c30ccfd09771"
+
 [[package]]
 name = "memchr"
 version = "2.5.0"
diff --git a/Cargo.toml b/Cargo.toml
index 9a38dbc..bab3a97 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,6 +17,8 @@ chrono = { version = "0.4.21", features = ["serde"] }
 tracing = "0.1.37"
 tracing-subscriber = "0.3.17"
 tower-http = { version = "0.4.3", features = ["trace"] }
+md5 = "0.7.0"
+base62 = "2.0.2"
 
 [dependencies.sqlx]
 version = "0.7.1"
diff --git a/Tests/key_generator.rs b/Tests/key_generator.rs
new file mode 100644
index 0000000..2ccf27a
--- /dev/null
+++ b/Tests/key_generator.rs
@@ -0,0 +1,8 @@
+use briefly::key_generator::generate;
+
+#[test]
+fn generate_seven_chars_key() {
+    let url = "https://www.rust-lang.org";
+    let generated = generate(url);
+    assert_eq!(generated, "e2XSHcR".to_string())
+}
diff --git a/src/key_generator.rs b/src/key_generator.rs
new file mode 100644
index 0000000..6718081
--- /dev/null
+++ b/src/key_generator.rs
@@ -0,0 +1,9 @@
+use base62::encode;
+use md5::compute;
+
+pub fn generate(value: &str) -> String {
+    let hash = compute(value);
+    let hash_bytes: [u8; 16] = hash.into();
+    let hash_u128: u128 = u128::from_le_bytes(hash_bytes);
+    encode(hash_u128)[..7].to_string()
+}
diff --git a/src/lib.rs b/src/lib.rs
index b6e12b2..24d561a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,5 @@
 pub mod configuration;
+pub mod key_generator;
 pub mod model;
 pub mod request_tracing;
 pub mod routes;
diff --git a/src/routes/full_url.rs b/src/routes/full_url.rs
index 2c8342d..1ced939 100644
--- a/src/routes/full_url.rs
+++ b/src/routes/full_url.rs
@@ -1,6 +1,9 @@
-use crate::{model::UrlRequestModel, schema::CreateShortUrlSchema, AppState};
+use crate::{
+    key_generator::generate, model::UrlRequestModel, schema::CreateShortUrlSchema, AppState,
+};
 use axum::{extract::State, Json};
 use chrono::Utc;
+use sqlx::Error;
 use std::sync::Arc;
 use uuid::Uuid;
 
@@ -8,23 +11,42 @@ pub async fn full_url(
     State(data): State<Arc<AppState>>,
     Json(payload): Json<CreateShortUrlSchema>,
 ) {
-    let query_result = sqlx::query_as!(
+    let mut retry_count = 3;
+
+    while retry_count > 0 {
+        let query_result = insert_in_db(&payload.url, State(data.clone())).await;
+
+        match query_result {
+            Ok(note) => {
+                println!("okay received testing: {:?}", note);
+                break;
+            }
+            Err(e) => {
+                println!("failed with error: {:?}", e);
+                //TODO : - For now assume is failing because of error code 23505, that stands for
+                //duplicate key
+                retry_count += 1;
+            }
+        }
+    }
+}
+
+async fn insert_in_db(
+    url: &str,
+    State(data): State<Arc<AppState>>,
+) -> Result<UrlRequestModel, Error> {
+    let uuid = Uuid::new_v4();
+    let modifier = uuid.to_string() + url;
+    let shortened = generate(&modifier);
+
+    sqlx::query_as!(
         UrlRequestModel,
         "INSERT INTO briefly (id, url, extension, created_at) VALUES ($1, $2, $3, $4) RETURNING *",
-        Uuid::new_v4(),
-        payload.url.to_string(),
-        Uuid::new_v4().to_string(), // TODO: - handle extension to be shortened url extension
+        uuid,
+        url.to_string(),
+        shortened,
         Utc::now()
     )
     .fetch_one(&data.db)
-    .await;
-
-    match query_result {
-        Ok(note) => {
-            println!("okay received testing: {:?}", note);
-        }
-        Err(e) => {
-            println!("{:?}", e);
-        }
-    }
+    .await
 }