Fixes #97: SQLite is now async, optimized, tests

2022-10-21 10:00:43 +02:00
parent b9da9b7965
commit c1a78e0105
65 changed files with 329 additions and 142 deletions
@@ -0,0 +1,79 @@
+/**
+ * cli.ts
+ *
+ * A simple clone of the sqlite3 command line
+ * interface, build using deno-sqlite.
+ *
+ * This is an example, meant to illustrate using
+ * the API provided by deno-sqlite.
+ */
+
+import { readLines, writeAll } from "https://deno.land/std@0.134.0/io/mod.ts";
+import AsciiTable from "https://deno.land/x/ascii_table@v0.1.0/mod.ts";
+import { DB } from "../mod.ts";
+
+const db = new DB(Deno.args[0] ?? undefined);
+
+async function print(str: string) {
+  const enc = new TextEncoder();
+  await writeAll(Deno.stdout, enc.encode(str));
+}
+
+async function prompt() {
+  await print("sqlite> ");
+}
+
+const tablesQuery = db.prepareQuery<[string]>(
+  "SELECT name FROM sqlite_master WHERE type = 'table' AND name NOT LIKE 'sqlite_%'",
+);
+
+const commands: Record<string, () => Promise<void>> = {
+  "tables": async () => {
+    for (const [name] of tablesQuery.iter()) {
+      await print(`${name}\n`);
+    }
+  },
+  "quit": async () => {
+    await print("\n");
+    Deno.exit(0);
+  },
+  "help": async () => {
+    await print(
+      "Type an SQL query or run a command.\nThe following commands are available:\n",
+    );
+    for (const key in commands) {
+      await print(`.${key}\n`);
+    }
+  },
+};
+
+await prompt();
+for await (const cmd of readLines(Deno.stdin)) {
+  if (cmd[0] === ".") {
+    const action = commands[cmd.slice(1)] ??
+      (() => print("Unrecognized command, try .help\n"));
+    await action();
+  } else {
+    try {
+      const query = db.prepareQuery(cmd);
+      const rows = query.all();
+      const cols = query.columns();
+      query.finalize();
+
+      if (cols.length) {
+        const table = new AsciiTable();
+        table.setHeading("#", ...cols.map(({ name }) => name));
+        for (const [idx, row] of rows.entries()) {
+          table.addRow(idx + 1, ...row);
+        }
+        print(table.toString());
+        print("\n");
+      } else {
+        print(`Executed query: ${db.changes} changes\n`);
+      }
+    } catch (err) {
+      console.error(err);
+    }
+  }
+  await prompt();
+}