From f5611c0bfdc73f76ef5330a17a49d4b5407ae395 Mon Sep 17 00:00:00 2001
From: Federico Igne <git@federicoigne.com>
Date: Fri, 29 Jul 2022 22:51:37 +0100
Subject: feat(GET /tag/{tags}): add ability to retrieve notes by tag(s)

Placeholder `{tags}` is substituted with one or more tags separated by
a plus sign `+`.
---
 README.md | 41 ++++++++++++++++++++++++++++++++++++-----
 1 file changed, 36 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 0f6df09..64de347 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,8 @@ mod note;
 
 <<req_get_notes>>
 
+<<req_get_tags>>
+
 <<req_post_notes>>
 ```
 
@@ -135,23 +137,22 @@ use actix_web::{HttpResponse,Responder,web,get,post};
 use actix_web::http::header::ContentType;
 ```
 
+Each request handlers is an *async* function that accepts zero or more parameters, extracted from a request (see [`FromRequest`](https://docs.rs/actix-web/latest/actix_web/trait.FromRequest.html) trait), and returns an [`HttpResponse`](https://docs.rs/actix-web/latest/actix_web/struct.HttpResponse.html).
+
 ## Resources
 
 - [Tutorial](https://web.archive.org/web/20220710213947/https://hub.qovery.com/guides/tutorial/create-a-blazingly-fast-api-in-rust-part-1/)
 - [Introduction to `actix`](https://actix.rs/docs/getting-started/)
 
-
 ## GET /notes
 
-Each request handlers is an *async* function that accepts zero or more parameters, extracted from a request (see [`FromRequest`](https://docs.rs/actix-web/latest/actix_web/trait.FromRequest.html) trait), and returns an [`HttpResponse`](https://docs.rs/actix-web/latest/actix_web/struct.HttpResponse.html).
-
-Here we are requesting the list of notes currently in the system.
+This handler allows to request the full list of notes currently in the system.
 The function takes 0 parameters and returns a JSON object.
 
 ```{#req_get_notes .rust}
 #[get("/notes")]
 pub async fn list() -> HttpResponse {
-  let mut notes: Notes;
+  let notes: Notes;
 
   <<notes_retrieve>>
 
@@ -163,6 +164,15 @@ pub async fn list() -> HttpResponse {
 
 ## POST /notes
 
+New notes can be added by POSTing a JSON array of `NoteRequest`s of the form
+
+```json
+{
+    "body": "This is a funny note",
+    "tags": [ "joyce", "funny", "example" ]
+}
+```
+
 ```{#req_post_notes .rust}
 #[post("/notes")]
 pub async fn add(new_notes: web::Json<NoteRequests>) -> impl Responder {
@@ -180,6 +190,26 @@ pub async fn add(new_notes: web::Json<NoteRequests>) -> impl Responder {
 }
 ```
 
+## GET /tag/{tags}
+
+This handler allows to query the set of notes for specific tags.
+One or more tags separated by `+` can be passed to the request.
+
+```{#req_get_tags .rust}
+#[get("/tag/{tags}")]
+pub async fn get_tags(tags: web::Path<String>) -> HttpResponse {
+  let tags = tags.split('+').map(|t| t.to_string()).collect::<Vec<_>>();
+
+  let notes: Notes;
+  <<notes_retrieve>>
+  let tagged = notes.into_iter().filter(|n| tags.iter().all(|t| n.tags.contains(t))).collect::<Vec<_>>();
+
+  HttpResponse::Ok()
+    .content_type(ContentType::json())
+    .json(tagged)
+}
+```
+
 # The program
 
 The main program is structured as follows
@@ -209,6 +239,7 @@ async fn main() -> std::io::Result<()> {
         App::new()
             .service(note::list)
             .service(note::add)
+            .service(note::get_tags)
     })
     .bind(("127.0.0.1", 8080))?
     .run()
-- 
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