initial commitHEADmaster

3 files changed, 191 insertions, 0 deletions

diff --git a/src/cors.rs b/src/cors.rs
new file mode 100644
index 0000000..700e4bb
--- /dev/null
+++ b/src/cors.rs
@@ -0,0 +1,25 @@
+use rocket::fairing::{Fairing, Info, Kind};
+use rocket::http::Header;
+use rocket::{Request, Response};
+
+pub struct CORS;
+
+#[rocket::async_trait]
+impl Fairing for CORS {
+    fn info(&self) -> Info {
+        Info {
+            name: "Add CORS headers to responses",
+            kind: Kind::Response,
+        }
+    }
+
+    async fn on_response<'r>(&self, _req: &'r Request<'_>, response: &mut Response<'r>) {
+        response.set_header(Header::new("Access-Control-Allow-Origin", "*"));
+        response.set_header(Header::new(
+            "Access-Control-Allow-Methods",
+            "POST, GET, PATCH, OPTIONS",
+        ));
+        response.set_header(Header::new("Access-Control-Allow-Headers", "*"));
+        response.set_header(Header::new("Access-Control-Allow-Credentials", "true"));
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..f28d6df
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,63 @@
+#[macro_use]
+extern crate rocket;
+#[macro_use]
+extern crate diesel;
+
+mod cors;
+mod kanta;
+mod pagination;
+use crate::diesel::QueryDsl;
+use crate::diesel::TextExpressionMethods;
+use crate::pagination::SortingAndPaging;
+use cors::CORS;
+use rocket::serde::json::Json as InOut;
+// use rocket::serde::msgpack::MsgPack as InOut;
+
+#[derive(FromForm)]
+struct ProductFilter {
+    prefix: Option<String>,
+    sort_by: Option<String>,
+    sort_direction: Option<String>,
+    page_num: Option<i64>,
+    page_size: Option<i64>,
+}
+
+#[get("/products?<filter..>")]
+async fn filter_products(
+    filter: ProductFilter,
+    db: kanta::Db,
+) -> Option<InOut<pagination::Page<kanta::Product>>> {
+    info!("prefix: {:?}", Some(filter.prefix.clone()));
+    db.run(move |conn| {
+        let mut query = kanta::products::table.into_boxed();
+        if let Some(i) = filter.prefix {
+            query = query.filter(kanta::products::title.like(format!("%{}%", i)));
+        }
+        query
+            .paginate(filter.page_num.unwrap_or(0))
+            .per_page(filter.page_size.unwrap_or(100))
+            .sort(
+                filter.sort_by.unwrap_or("created_at".to_string()),
+                filter.sort_direction.unwrap_or("".to_string()),
+            )
+            .load_and_count_items::<kanta::Product>(conn)
+    })
+    .await
+    .map(InOut)
+    .ok()
+}
+
+#[get("/")]
+async fn index() -> String {
+    "Server is running".to_string()
+}
+
+#[launch]
+fn rocket() -> _ {
+    kanta::mount_at(
+        rocket::build()
+            .attach(CORS)
+            .mount("/", routes![index, filter_products]),
+        "/",
+    )
+}
diff --git a/src/pagination.rs b/src/pagination.rs
new file mode 100644
index 0000000..961b079
--- /dev/null
+++ b/src/pagination.rs
@@ -0,0 +1,103 @@
+use diesel::prelude::*;
+use diesel::query_builder::*;
+use diesel::query_dsl::methods::LoadQuery;
+use diesel::sql_types::BigInt;
+use diesel::sqlite::Sqlite;
+use rocket::serde::Serialize;
+
+pub trait SortingAndPaging: Sized {
+    fn paginate(self, page: i64) -> SortedAndPaginated<Self>;
+}
+
+impl<T> SortingAndPaging for T {
+    fn paginate(self, page: i64) -> SortedAndPaginated<Self> {
+        SortedAndPaginated {
+            query: self,
+            sort_by: "".to_string(),
+            sort_direction: "".to_string(),
+            per_page: 100,
+            page,
+        }
+    }
+}
+
+#[derive(Serialize)]
+#[serde(crate = "rocket::serde")]
+pub struct Page<T> {
+    pub data: Vec<T>,
+    pub page_num: i64,
+    pub page_size: i64,
+    pub total_elements: i64,
+}
+
+impl<T> Page<T> {
+    pub fn new(data: Vec<T>, page_num: i64, page_size: i64, total_elements: i64) -> Page<T> {
+        Page {
+            data,
+            page_num,
+            page_size,
+            total_elements,
+        }
+    }
+}
+
+#[derive(Debug, Clone, QueryId)]
+pub struct SortedAndPaginated<T> {
+    query: T,
+    sort_by: String,
+    sort_direction: String,
+    page: i64,
+    per_page: i64,
+}
+
+impl<T> SortedAndPaginated<T> {
+    pub fn per_page(self, per_page: i64) -> Self {
+        SortedAndPaginated { per_page, ..self }
+    }
+
+    pub fn sort(self, sort_by: String, sort_direction: String) -> Self {
+        SortedAndPaginated {
+            sort_by,
+            sort_direction,
+            ..self
+        }
+    }
+
+    pub fn load_and_count_items<U>(self, conn: &SqliteConnection) -> QueryResult<Page<U>>
+    where
+        Self: LoadQuery<SqliteConnection, (U, i64)>,
+    {
+        let page = self.page;
+        let per_page = self.per_page;
+        let results = self.load::<(U, i64)>(conn)?;
+        let total = results.get(0).map(|x| x.1).unwrap_or(0);
+        let records = results.into_iter().map(|x| x.0).collect();
+        Ok(Page::new(records, page, per_page, total))
+    }
+}
+
+impl<T: Query> Query for SortedAndPaginated<T> {
+    type SqlType = (T::SqlType, BigInt);
+}
+
+impl<T> RunQueryDsl<SqliteConnection> for SortedAndPaginated<T> {}
+
+impl<T> QueryFragment<Sqlite> for SortedAndPaginated<T>
+where
+    T: QueryFragment<Sqlite>,
+{
+    fn walk_ast(&self, mut out: AstPass<Sqlite>) -> QueryResult<()> {
+        out.push_sql("SELECT *, COUNT(*) OVER () FROM (");
+        self.query.walk_ast(out.reborrow())?;
+        out.push_sql(") t ");
+        if &self.sort_by.as_str().len() > &0 {
+            out.push_sql(format!(" ORDER BY {} {}", &self.sort_by, &self.sort_direction).as_str());
+        }
+        out.push_sql(" LIMIT ");
+        out.push_bind_param::<BigInt, _>(&self.per_page)?;
+        out.push_sql(" OFFSET ");
+        let offset = (self.page - 1) * self.per_page;
+        out.push_bind_param::<BigInt, _>(&offset)?;
+        Ok(())
+    }
+}