Add data extract service

app/src/api/services/dataExtract.ts

@@ -0,0 +1,59 @@
+import path from 'path';
+
+import db from '../../db';
+
+interface DataExtractRow {
+    extract_id: number;
+    extracted_on: Date;
+    extract_path: string;
+}
+
+interface DataExtract {
+    extract_id: number;
+    extracted_on: Date;
+    download_path: string;
+}
+
+export async function listDataExtracts(): Promise<DataExtract[]> {
+    try {
+        const extractRecords = await db.many<DataExtractRow>(
+            `SELECT
+                extract_id, extracted_on, extract_path
+            FROM bulk_extracts`
+        );
+
+        return extractRecords.map(getDataExtractFromRow);
+    } catch (err) {
+        console.error('Error:', err);
+        return undefined;
+    }
+}
+
+export async function getDataExtractById(extractId: number): Promise<DataExtract> {
+    try {
+        const extractRecord = await db.one<DataExtractRow>(
+            `SELECT 
+                extract_id, extracted_on, extract_path
+            FROM bulk_extracts
+            WHERE extract_id = $1
+            `, [extractId]);
+
+        return getDataExtractFromRow(extractRecord);
+    } catch (err) {
+        console.error('Error:', err);
+        return undefined;
+    }
+}
+
+function getDataExtractFromRow(er: DataExtractRow): DataExtract {
+    return {
+        extract_id: er.extract_id,
+        extracted_on: er.extracted_on,
+        download_path: getDownloadLinkForExtract(er)
+    }
+}
+
+function getDownloadLinkForExtract(extract: DataExtractRow): string {
+    const file_name = path.basename(extract.extract_path);
+    return `/downloads/extracts/${file_name}`; // TODO: potentially move base path to env var
+}