Merge pull request #30 from kanko-travel/idempotent_create

Idempotent create

model/src/crud/create.rs

@@ -3,20 +3,26 @@ use sqlx::{postgres::PgRow, FromRow, PgConnection};
 use crate::Error;
 use crate::{crud::util::build_query, FieldValue, Model};
 
-#[derive(Clone, Debug)]
+use super::util::build_query_as;
+
+#[derive(Debug)]
 pub struct Create<'a, T: Model> {
-    value: &'a T,
+    value: &'a mut T,
+    idempotent: bool,
 }
 
 impl<'a, T> Create<'a, T>
 where
     T: Model + for<'b> FromRow<'b, PgRow> + Unpin + Sized + Send,
 {
-    pub(crate) fn new(value: &'a T) -> Self {
-        Self { value }
+    pub(crate) fn new(value: &'a mut T) -> Self {
+        Self {
+            value,
+            idempotent: false,
+        }
     }
 
-    pub async fn execute(&self, executor: &mut PgConnection) -> Result<(), Error> {
+    pub async fn execute(&mut self, executor: &mut PgConnection) -> Result<(), Error> {
         let table_name = T::table_name();
         let fields = self.value.fields()?;
 
@@ -33,13 +39,30 @@ where
             .collect::<Vec<String>>()
             .join(", ");
 
+        let var_bindings: Vec<FieldValue> = fields.into_iter().map(|(_, value)| value).collect();
+
+        if self.idempotent {
+            let primary_key_index = format!("{}_pkey", table_name);
+
+            let statement = format!(
+                "INSERT INTO {} ({}) VALUES ({}) ON CONFLICT ON CONSTRAINT {} DO NOTHING RETURNING *",
+                table_name, columns, placeholder_values, primary_key_index
+            );
+
+            let created: T = build_query_as(&statement, var_bindings)
+                .fetch_one(executor)
+                .await?;
+
+            *self.value = created;
+
+            return Ok(());
+        }
+
         let statement = format!(
             "INSERT INTO {} ({}) VALUES ({})",
             table_name, columns, placeholder_values
         );
 
-        let var_bindings: Vec<FieldValue> = fields.into_iter().map(|(_, value)| value).collect();
-
         build_query(&statement, var_bindings)
             .execute(executor)
             .await?;

model/src/crud/mod.rs

@@ -46,7 +46,7 @@ where
         DeleteAssociation::new(self, relation_name, associated_id)
     }
 
-    fn create<'a>(&'a self) -> Create<'a, Self> {
+    fn create<'a>(&'a mut self) -> Create<'a, Self> {
         Create::new(self)
     }
 

model/src/sort_by/grammar.lalrpop

@@ -1,11 +1,6 @@
-use std::str::FromStr;
-use uuid::Uuid;
-use rust_decimal::Decimal;
-use chrono::{DateTime, NaiveDate};
 use lalrpop_util::ParseError;
-use crate::filter::ast::{Expr, LogicOp, CompOp, Var};
-use crate::filter::util::apply_string_escapes;
-use crate::{FieldType, FieldValue, ModelDef};
+use crate::filter::ast::Var;
+use crate::{ModelDef};
 
 grammar(model_def: &ModelDef);
 

model/tests/crud.rs

@@ -54,7 +54,7 @@ async fn test_create() {
 
     let mut records = records.into_iter();
 
-    let record = records.next().unwrap();
+    let mut record = records.next().unwrap();
 
     record.create().execute(&mut tx).await.unwrap();
 
@@ -83,7 +83,7 @@ async fn test_upsert() {
 
     let mut records = records.into_iter();
 
-    let record = records.next().unwrap();
+    let mut record = records.next().unwrap();
 
     record.create().execute(&mut tx).await.unwrap();
 

model/tests/pagination.rs

@@ -34,7 +34,7 @@ async fn setup_tables(tx: &mut Transaction<'_, Postgres>) {
 async fn insert_records(tx: &mut Transaction<'_, Postgres>) {
     let records = read_records();
 
-    for record in records.into_iter() {
+    for mut record in records.into_iter() {
         record.create().execute(tx).await.unwrap();
     }
 }