commit 0bec2a0e8ca714ce9848a9b0202c66891ecb4713
Author: cahe <me@cahe.space>
Date:   Sun Sep 20 13:24:12 2020 -0300

    Base structure

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..53eaa21
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/target
+**/*.rs.bk
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..9cc2bff
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "simple"
+version = "0.1.0"
+authors = ["cahe"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+warp = "0.2"
+tokio = { version = "0.2", features = ["macros"] }
+serde = { version = "1.0", features = ["derive"] }
+serde_json = { version = "1.0" }
+sqlx = { version = "0.4.0-beta.1", default-features = false, features = [ "postgres", "runtime-tokio", "macros" ] }
diff --git a/src/app/mod.rs b/src/app/mod.rs
new file mode 100644
index 0000000..ee09d7f
--- /dev/null
+++ b/src/app/mod.rs
@@ -0,0 +1 @@
+pub mod robots;
diff --git a/src/app/robots.rs b/src/app/robots.rs
new file mode 100644
index 0000000..156b354
--- /dev/null
+++ b/src/app/robots.rs
@@ -0,0 +1,119 @@
+use serde::{Serialize, Deserialize};
+
+use crate::simple::database::PgSharedPool;
+
+use crate::base::robots;
+use crate::data::postgres;
+
+use crate::simple::handling::HandlingError;
+
+#[derive(Serialize, Deserialize)]
+pub struct GetRobot {
+    #[serde(skip_deserializing)]
+    pub id : i64,
+    pub name : String
+}
+
+type Model = GetRobot;
+
+impl std::convert::From<robots::Robot> for GetRobot {
+    fn from(r : robots::Robot) -> GetRobot {
+        GetRobot{
+            id: r.id,
+            name: r.name
+        }
+    }
+}
+
+impl std::convert::Into<robots::Robot> for (i64, GetRobot) {
+    fn into(self) -> robots::Robot {
+        robots::Robot{
+            id: self.0,
+            name: self.1.name
+        }
+    }
+}
+
+pub async fn add_robot(pool : PgSharedPool, r : GetRobot) -> Result<GetRobot, HandlingError> {
+    let mut tx = pool.begin()
+        .await
+        .map(|c| Box::new(c))
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    let mut repo = postgres::RobotsImpl::new(&mut tx);
+    let id = robots::add(&mut repo, robots::Robot{id: 0, name: r.name}).await?;
+    let robot = repo.get_by_id(id).await?;
+
+    tx
+        .commit()
+        .await
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    Ok(robot.into())
+}
+
+pub async fn get_robot(pool : PgSharedPool, id : i64) -> Result<GetRobot, HandlingError> {
+    let mut tx = pool.begin()
+        .await
+        .map(|c| Box::new(c))
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    let mut repo = postgres::RobotsImpl::new(&mut tx);
+    Ok(repo.get_by_id(id).await?.into())
+}
+
+pub async fn get_all(
+    pool : PgSharedPool, offset : i64, limit : i64
+) -> Result<(Vec<Model>, bool), HandlingError> {
+    let mut tx = pool.begin()
+        .await
+        .map(|c| Box::new(c))
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    let mut repo = postgres::ModelImpl::new(&mut tx);
+    let (items, next) = repo.get_all()?
+        .paginate(offset, limit)
+        .await?;
+
+    let data = items
+        .into_iter()
+        .map(|r| r.into())
+        .collect();
+
+    Ok((data, next))
+}
+
+pub async fn update_robot(pool : PgSharedPool, id : i64, r : GetRobot) -> Result<GetRobot, HandlingError> {
+    let mut tx = pool.begin()
+        .await
+        .map(|c| Box::new(c))
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    let mut repo = postgres::RobotsImpl::new(&mut tx);
+    let _ : () = robots::update(&mut repo, (id, r).into()).await?;
+    let robot = repo.get_by_id(id).await?;
+
+    tx
+        .commit()
+        .await
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    Ok(robot.into())
+}
+
+pub async fn delete_robot(pool : PgSharedPool, id : i64) -> Result<(), HandlingError> {
+    let mut tx = pool.begin()
+        .await
+        .map(|c| Box::new(c))
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    let mut repo = postgres::ModelImpl::new(&mut tx);
+    let _ : () = robots::delete(&mut repo, id).await?;
+
+    tx
+        .commit()
+        .await
+        .map_err(|e| HandlingError::DBError(e))?;
+
+    Ok(())
+}
diff --git a/src/base/mod.rs b/src/base/mod.rs
new file mode 100644
index 0000000..ee09d7f
--- /dev/null
+++ b/src/base/mod.rs
@@ -0,0 +1 @@
+pub mod robots;
diff --git a/src/base/robots.rs b/src/base/robots.rs
new file mode 100644
index 0000000..124135e
--- /dev/null
+++ b/src/base/robots.rs
@@ -0,0 +1,28 @@
+use std::future::Future;
+use std::boxed::Box;
+use std::pin::Pin;
+
+use crate::simple::handling::HandlingError;
+
+pub struct Robot {
+    pub id : i64,
+    pub name : String
+}
+
+pub trait DefaultRepository {
+    fn add(&mut self, r : Robot) -> Pin<Box<dyn Future<Output = Result<i64, HandlingError>> + Send + '_>>;
+    fn update(&mut self, r : Robot) -> Pin<Box<dyn Future<Output = Result<(), HandlingError>> + Send + '_>>;
+    fn delete(&mut self, id : i64) -> Pin<Box<dyn Future<Output = Result<(), HandlingError>> + Send + '_>>;
+}
+
+pub async fn add(repo : &mut impl DefaultRepository, r : Robot) -> Result<i64, HandlingError> {
+    repo.add(r).await
+}
+
+pub async fn update(repo : &mut impl DefaultRepository, r : Robot) -> Result<(), HandlingError> {
+    repo.update(r).await
+}
+
+pub async fn delete(repo : &mut impl DefaultRepository, id : i64) -> Result<(), HandlingError> {
+    repo.delete(id).await
+}
diff --git a/src/data/mod.rs b/src/data/mod.rs
new file mode 100644
index 0000000..26e9103
--- /dev/null
+++ b/src/data/mod.rs
@@ -0,0 +1 @@
+pub mod postgres;
diff --git a/src/data/postgres.rs b/src/data/postgres.rs
new file mode 100644
index 0000000..e9b4feb
--- /dev/null
+++ b/src/data/postgres.rs
@@ -0,0 +1,172 @@
+use std::boxed::Box;
+use std::pin::Pin;
+
+use crate::simple::handling::{HandlingError};
+use crate::base::robots;
+
+use std::future::Future;
+
+use sqlx::FromRow;
+use sqlx::Done;
+
+pub struct Collection<'a> {
+    tx : &'a mut Box<sqlx::Transaction<'static, sqlx::Postgres>>,
+    q : sqlx::query::Query<'a, sqlx::Postgres, sqlx::postgres::PgArguments>,
+    q_id : Option<i64>
+}
+
+impl Collection<'_> {
+    pub fn by_id(self, id : i64) -> Self {
+        Self {
+            tx: self.tx,
+            q: self.q,
+            q_id: Some(id)
+        }
+    }
+
+    pub async fn fetch(self, offset : i64, limit : i64) -> Result<Vec<robots::Robot>, HandlingError> {
+        let result = self.q
+            .bind(self.q_id.is_some())
+            .bind(self.q_id.unwrap_or_default())
+            .bind(offset)
+            .bind(limit)
+            .fetch_all(self.tx.as_mut())
+            .await;
+        match result {
+            Ok(v) => v
+                .into_iter()
+                .map(|d| {
+                    let (id, name) = <(i64, String)>::from_row(&d)?;
+                    Ok(robots::Robot{
+                        id: id,
+                        name: name
+                    })
+                })
+                .collect(),
+            Err(e) => Err(HandlingError::DBError(e))
+        }
+    }
+
+    pub async fn paginate(self, offset : i64, limit : i64) -> Result<(Vec<robots::Robot>, bool), HandlingError> {
+        let mut items = self.fetch(offset, limit+1).await?;
+        if items.len() > (limit as usize) {
+            let _ = items.pop();
+            Ok((items, true))
+        } else {
+            Ok((items, false))
+        }
+    }
+}
+
+pub struct RobotsImpl<'a> {
+    pub tx : &'a mut Box<sqlx::Transaction<'static, sqlx::Postgres>>
+}
+
+pub type ModelImpl<'a> = RobotsImpl<'a>;
+
+impl<'a> RobotsImpl<'_> {
+    pub fn new<'b>(tx : &'b mut Box<sqlx::Transaction<'static, sqlx::Postgres>>) -> RobotsImpl<'b> {
+        RobotsImpl{tx: tx}
+    }
+
+    async fn add(&mut self, r : robots::Robot) -> Result<i64, HandlingError> {
+        let result = sqlx::query(
+            "INSERT INTO robots (name) VALUES ($1::TEXT) RETURNING id")
+            .bind(r.name)
+            .fetch_one(self.tx.as_mut())
+            .await;
+        match result {
+            Ok(v) => {
+                let (id,) = <(i64,)>::from_row(&v)?;
+                Ok(id)
+            },
+            Err(sqlx::Error::RowNotFound) => Err(HandlingError::NotFound),
+            Err(e) => Err(HandlingError::DBError(e))
+        }
+    }
+
+    pub async fn get_by_id(&mut self, id : i64) -> Result<robots::Robot, HandlingError> {
+        let result = sqlx::query(
+            "SELECT * FROM robots WHERE id = $1::INTEGER")
+            .bind(id)
+            .fetch_one(self.tx.as_mut())
+            .await;
+        match result {
+            Ok(v) => {
+                let (id, name) = <(i64, String)>::from_row(&v)?;
+                Ok(robots::Robot{
+                    id: id,
+                    name: name
+                })
+            },
+            Err(sqlx::Error::RowNotFound) => Err(HandlingError::NotFound),
+            Err(e) => Err(HandlingError::DBError(e))
+        }
+    }
+
+    pub fn get_all(&'a mut self) -> Result<Collection<'a>, HandlingError> {
+        let all = sqlx::query::<sqlx::Postgres>(
+            "SELECT id, name
+                FROM robots
+            WHERE
+                (CASE WHEN $1::BOOLEAN THEN (id = $2::INTEGER) ELSE TRUE END)
+            OFFSET $3
+            LIMIT $4"
+        );
+        Ok(Collection{
+            tx: self.tx,
+            q: all,
+            q_id: None
+        })
+    }
+
+    async fn update(&mut self, r : robots::Robot) -> Result<(), HandlingError> {
+        let result = sqlx::query(
+            "UPDATE robots SET name = $1::TEXT WHERE id = $2::INTEGER")
+            .bind(r.name)
+            .bind(r.id)
+            .execute(self.tx.as_mut())
+            .await;
+        match result {
+            Ok(v) => match v.rows_affected() {
+                1 => Ok(()),
+                0 => Err(HandlingError::NotFound),
+                _ => Err(HandlingError::InternalError)
+            },
+            Err(sqlx::Error::RowNotFound) => Err(HandlingError::NotFound),
+            Err(e) => Err(HandlingError::DBError(e))
+        }
+    }
+
+
+
+    async fn delete(&mut self, id : i64) -> Result<(), HandlingError> {
+        let result = sqlx::query(
+            "DELETE FROM robots WHERE id = $1::INTEGER")
+            .bind(id)
+            .execute(self.tx.as_mut())
+            .await;
+        match result {
+            Ok(v) => match v.rows_affected() {
+                1 => Ok(()),
+                0 => Err(HandlingError::NotFound),
+                _ => Err(HandlingError::InternalError)
+            },
+            Err(e) => Err(HandlingError::DBError(e))
+        }
+    }
+}
+
+impl robots::DefaultRepository for RobotsImpl<'_> {
+    fn add(&mut self, r : robots::Robot) -> Pin<Box<dyn Future<Output = Result<i64, HandlingError>> + Send + '_>> {
+        Box::pin(self.add(r))
+    }
+
+    fn update(&mut self, r : robots::Robot) -> Pin<Box<dyn Future<Output = Result<(), HandlingError>> + Send + '_>> {
+        Box::pin(self.update(r))
+    }
+
+    fn delete(&mut self, id : i64) -> Pin<Box<dyn Future<Output = Result<(), HandlingError>> + Send + '_>> {
+        Box::pin(self.delete(id))
+    }
+}
diff --git a/src/http/mod.rs b/src/http/mod.rs
new file mode 100644
index 0000000..c0cc3b5
--- /dev/null
+++ b/src/http/mod.rs
@@ -0,0 +1,86 @@
+pub mod robots;
+
+use serde::Serialize;
+use warp::Filter;
+use warp::Reply;
+
+use warp::http::StatusCode;
+
+use crate::simple::handling::HandlingError;
+use crate::simple::http::APIBuilder;
+
+impl warp::reject::Reject for HandlingError {}
+
+#[derive(Serialize)]
+struct APIError {
+    code: i64,
+    message: String,
+}
+
+fn build_error_response(e: &HandlingError) -> Result<warp::reply::Response, warp::http::Error> {
+    let (status, code, message) = match e {
+        HandlingError::DBError(_e) => (
+            StatusCode::INTERNAL_SERVER_ERROR, 1, format!("Database access error")
+        ),
+        HandlingError::NotFound => (
+            StatusCode::NOT_FOUND, 2, format!("Not Found")
+        ),
+        HandlingError::InternalError => (
+            StatusCode::INTERNAL_SERVER_ERROR, 3, format!("Internal unexpected error")
+        ),
+    };
+
+    let body = warp::reply::json(&APIError {
+        code: code,
+        message: message,
+    });
+
+    Ok(warp::reply::with_status(body, status).into_response())
+}
+
+async fn handle_rejection(
+    r: warp::reject::Rejection,
+) -> Result<warp::reply::Response, warp::reject::Rejection> {
+    eprintln!("{:#?}", r);
+    r.find::<HandlingError>()
+        .map(|e| {
+            build_error_response(e)
+                .unwrap_or(
+                    StatusCode::INTERNAL_SERVER_ERROR
+                        .into_response()
+                )
+        })
+        .ok_or(r)
+}
+
+pub async fn listen(
+    db_pool: crate::simple::database::PgSharedPool,
+    addr: impl Into<std::net::SocketAddr> + 'static,
+) {
+    // build a base Filter for our API so that any request of any kind to "/"
+    // will return "200 OK" with an empty response body
+    let base = warp::any()
+        // match a path termination by a "/" character or lack thereof
+        .and(warp::path::end())
+        // reply with a "200 OK" with an empty response body
+        .map(|| warp::reply())
+        // box the filter so it may be passed be passed around easily
+        .boxed();
+
+    // begin building the API structure from the base Filter
+    // right now the pool of database connections is the only
+    // shared resource that we want to passa around when handling requests
+    let api = APIBuilder::new(base, db_pool)
+        // mount the "/robots" base prefix for creating
+        // and listing all robots in the database
+        .route(robots::all)
+        // mount the "/robot/{id}" prefix for retrieving and updating robots information
+        .route(robots::with_id)
+        // build the final filter that we'll be served
+        .build()
+        // attach a recover to handle rejections
+        .recover(handle_rejection);
+
+    // run the server returning a Future that will be run indefinitely
+    warp::serve(api).run(addr).await
+}
diff --git a/src/http/robots.rs b/src/http/robots.rs
new file mode 100644
index 0000000..ee1d353
--- /dev/null
+++ b/src/http/robots.rs
@@ -0,0 +1,111 @@
+use warp::Filter;
+
+use crate::simple::database::PgSharedPool;
+use crate::simple::http::reply_json;
+
+use serde::{Deserialize, Serialize};
+
+use warp::http::StatusCode;
+
+use crate::app;
+
+#[derive(Deserialize)]
+struct PaginationOptions {
+    pub offset: i64,
+    pub limit: i64,
+}
+
+#[derive(Serialize)]
+struct Pagination<T> {
+    pub data: Vec<T>,
+    pub next: bool,
+}
+
+async fn create(
+    pool: PgSharedPool,
+    r: app::robots::GetRobot,
+) -> Result<impl warp::Reply, warp::Rejection> {
+    reply_json(app::robots::add_robot(pool, r).await)
+}
+
+async fn get(
+    pool: PgSharedPool,
+    id: i64
+) -> Result<impl warp::Reply, warp::Rejection> {
+    reply_json(app::robots::get_robot(pool, id).await)
+}
+
+async fn update(
+    pool: PgSharedPool,
+    id: i64,
+    r: app::robots::GetRobot,
+) -> Result<impl warp::Reply, warp::Rejection> {
+    reply_json(app::robots::update_robot(pool, id, r).await)
+}
+
+async fn get_all(
+    pool: PgSharedPool,
+    p: PaginationOptions,
+) -> Result<impl warp::Reply, warp::Rejection> {
+    reply_json(
+        app::robots::get_all(pool, p.offset, p.limit)
+            .await
+            .map(|(r, next)| Pagination {
+                data: r,
+                next: next,
+            }),
+    )
+}
+
+async fn delete(
+    pool : PgSharedPool,
+    id : i64
+) -> Result<impl warp::Reply, warp::Rejection> {
+    match app::robots::delete_robot(pool, id).await {
+        Ok(_) => Ok(warp::reply::with_status(warp::reply(), StatusCode::NO_CONTENT)),
+        Err(e) => Err(warp::reject::custom(e))
+    }
+}
+
+pub fn all(
+    base: warp::filters::BoxedFilter<(impl warp::Reply + 'static,)>,
+    pool: PgSharedPool
+) -> warp::filters::BoxedFilter<(impl warp::Reply,)> {
+    let prefix = warp::path!("robots").map(move || pool.clone());
+
+    base.or(prefix
+        .clone()
+        .and(warp::filters::method::post())
+        .and(warp::body::json())
+        .and_then(create))
+        .or(prefix
+            .clone()
+            .and(warp::filters::method::get())
+            .and(warp::filters::query::query())
+            .and_then(get_all))
+        .boxed()
+}
+
+pub fn with_id(
+    base: warp::filters::BoxedFilter<(impl warp::Reply + 'static,)>,
+    pool: PgSharedPool,
+) -> warp::filters::BoxedFilter<(impl warp::Reply,)> {
+    let prefix = warp::path!("robot" / i64)
+        .map(move |id| (pool.clone(), id))
+        .untuple_one();
+
+    base.or(prefix
+        .clone()
+        .and(warp::filters::method::get())
+        .and_then(get))
+        .or(prefix
+            .clone()
+            .and(warp::filters::method::put())
+            .and(warp::body::json())
+            .and_then(update))
+        .or(prefix
+            .clone()
+            .and(warp::filters::method::delete())
+            .and_then(delete))
+        .boxed()
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..adb8b1a
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,12 @@
+mod simple;
+
+mod http;
+mod app;
+mod base;
+mod data;
+
+#[tokio::main]
+async fn main() -> Result<(), sqlx::Error> {
+    let db_pool = simple::database::connect_pool().await?;
+    Ok(http::listen(db_pool, ([127, 0, 0, 1], 8000)).await)
+}
diff --git a/src/simple/database.rs b/src/simple/database.rs
new file mode 100644
index 0000000..93d2b8d
--- /dev/null
+++ b/src/simple/database.rs
@@ -0,0 +1,12 @@
+pub type PgSharedPool = std::sync::Arc<sqlx::Pool<sqlx::Postgres>>;
+
+pub async fn connect_pool() -> Result<PgSharedPool, sqlx::Error> {
+    Ok(
+        std::sync::Arc::new(
+            sqlx::postgres::PgPoolOptions::new()
+                .max_connections(5)
+                .connect("postgresql://postgres:chapuleta@127.0.0.1:5432")
+                .await?
+        )
+    )
+}
diff --git a/src/simple/handling.rs b/src/simple/handling.rs
new file mode 100644
index 0000000..681679e
--- /dev/null
+++ b/src/simple/handling.rs
@@ -0,0 +1,12 @@
+#[derive(Debug)]
+pub enum HandlingError {
+    DBError(sqlx::Error),
+    NotFound,
+    InternalError
+}
+
+impl From<sqlx::Error> for HandlingError {
+    fn from(e : sqlx::Error) -> HandlingError {
+        HandlingError::DBError(e)
+    }
+}
diff --git a/src/simple/http.rs b/src/simple/http.rs
new file mode 100644
index 0000000..3c08655
--- /dev/null
+++ b/src/simple/http.rs
@@ -0,0 +1,44 @@
+use warp::Filter;
+
+pub struct APIBuilder<T, S>
+where
+    T: Filter,
+    S: Clone,
+{
+    routes: T,
+    shared: S,
+}
+
+impl<T, S> APIBuilder<T, S>
+where
+    T: Filter,
+    S: Clone,
+{
+    pub fn new(base: T, shared: S) -> Self {
+        APIBuilder {
+            shared: shared,
+            routes: base,
+        }
+    }
+
+    pub fn route<U, F>(self, build: F) -> APIBuilder<U, S>
+    where
+        U: Filter,
+        F: FnOnce(T, S) -> U,
+    {
+        APIBuilder::new(build(self.routes, self.shared.clone()), self.shared)
+    }
+
+    pub fn build(self) -> T {
+        self.routes
+    }
+}
+
+pub fn reply_json<T, E>(r: Result<T, E>) -> Result<impl warp::Reply, warp::Rejection>
+where
+    T: serde::Serialize,
+    E: warp::reject::Reject,
+{
+    r.map(|s| warp::reply::json(&s))
+        .map_err(warp::reject::custom)
+}
diff --git a/src/simple/init.rs b/src/simple/init.rs
new file mode 100644
index 0000000..e69de29
diff --git a/src/simple/mod.rs b/src/simple/mod.rs
new file mode 100644
index 0000000..6f97325
--- /dev/null
+++ b/src/simple/mod.rs
@@ -0,0 +1,5 @@
+pub mod database;
+pub mod handling;
+pub mod init;
+pub mod http;
+