wip: add sqlx setup

.gitignore

@@ -7,3 +7,4 @@ secring.*
 # Added by cargo
 
 /target
+.env

.justfile

@@ -0,0 +1,4 @@
+set dotenv-load := true
+
+dev:
+  cargo run --bin cli -- query "SELECT * FROM sources;"

Cargo.toml

@@ -5,3 +5,12 @@ edition = "2021"
 
 [dependencies]
 clap = { version = "4.5.26", features = ["derive", "env"] }
+futures = "0.3.31"
+sqlx = { version = "0.8", features = [
+  "runtime-tokio",
+  "tls-native-tls",
+  "postgres",
+  "sqlite",
+  "chrono",
+] }
+tokio = {version =  "1.43.0", features = ["full"]}

src/bin/cli/main.rs

@@ -1,4 +1,8 @@
 use clap::{Parser, Subcommand};
+use futures::TryStreamExt;
+use sqlx::postgres::PgPool;
+use sqlx::Column;
+use sqlx::Row;
 
 #[derive(Parser)]
 #[command(version, about, long_about = None)]
@@ -21,14 +25,33 @@ enum Commands {
     },
 }
 
-fn main() {
+#[tokio::main]
+async fn main() {
     let cli = Cli::parse();
 
+    let url = cli.db_url.unwrap();
+
     // You can check for the existence of subcommands, and if found use their
     // matches just as you would the top level cmd
     match &cli.command {
-        Commands::Query { sql } => {
-            println!("Provided query: {sql:?}");
-        }
+        Commands::Query { sql } => handle_query(url, sql).await.unwrap(),
     }
 }
+
+async fn handle_query(url: String, query: &String) -> Result<(), sqlx::Error> {
+    let pool = PgPool::connect(url.as_str()).await?;
+
+    let mut rows = sqlx::query(query.as_str()).fetch(&pool);
+
+    while let Some(row) = rows.try_next().await? {
+        // map the row into a user-defined domain type
+        let columns = row.columns();
+
+        for col in columns {
+            let value = String::from(row.get(col.ordinal()));
+            println!("Column {} value: {}", col.name(), value);
+        }
+    }
+
+    return Ok(());
+}

src/lib.rs

@@ -0,0 +1,18 @@
+pub mod sql;
+
+struct Column<T> {
+    sql_type: String,
+    value: T,
+}
+
+enum ColumnType {
+    I8(Column<i8>),
+    String(Column<String>),
+    Bool(Column<bool>),
+    I16(Column<i16>),
+    I32(Column<i32>),
+    I64(Column<i64>),
+    F32(Column<f32>),
+    F64(Column<f64>),
+    DateTime(Column<String>),
+}

src/sql.rs

@@ -0,0 +1 @@
+pub mod parser;

src/sql/parser.rs

@@ -0,0 +1,72 @@
+use crate::{Column, ColumnType};
+use sqlx::Column as _;
+use sqlx::Row as _;
+
+/// The postgres-crate does not provide a default mapping to fallback to String for all
+/// types: row.get is generic and without a type assignment the FromSql-Trait cannot be inferred.
+/// This function matches over the current column-type and does a manual conversion
+pub fn reflective_get(row: &impl sqlx::Row, index: usize) -> Option<ColumnType> {
+    let type_info = row.columns().get(index)?.type_info();
+    let column_type = type_info.name();
+    // see https://docs.rs/sqlx/0.4.0-beta.1/sqlx/postgres/types/index.html
+
+    match column_type {
+        "bool" => {
+            let v: bool = row.try_get(index)?;
+            Some(ColumnType::Bool(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        "varchar" | "char(n)" | "text" | "name" => row.get(index),
+        "char" => {
+            let v = row.get::<_, i8>(index);
+            Some(ColumnType::I8(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        "smallserial" | "smallint" => {
+            let v = row.get::<_, Option<i16>>(index);
+            Some(ColumnType::I16(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        "int" | "int4" | "serial" => {
+            let v = row.get::<_, Option<i32>>(index);
+            Some(ColumnType::I32(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        "int8" | "bigserial" | "bigint" => {
+            let v = row.get::<_, Option<i64>>(index);
+            Some(ColumnType::I64(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        "float4" | "real" => {
+            let v = row.get::<_, Option<f32>>(index);
+            Some(ColumnType::F32(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        "float8" | "double precision" => {
+            let v = row.get::<_, Option<f64>>(index);
+            Some(ColumnType::F64(Column {
+                sql_type: String::from(column_type),
+                value: v,
+            }))
+        }
+        // "timestamp" | "timestamptz" => {
+        //     // with-chrono feature is needed for this
+        //     let v: Option<SystemTime> = row.get(index);
+        //     let v = DateTime::<chrono::Utc>::from(v.unwrap());
+        //     Some(v.to_string())
+        // }
+        &_ => None,
+    }
+}