Implement sequence patching endpoint.

Allows us to change remarks and meta fields in sequences.

lib/www/server/api/index.js

@@ -99,10 +99,10 @@ app.map({
 	'/project/:project/sequence/': {
 		get: [ mw.sequence.list ],
 	},
-// 	'/project/:project/sequence/:line': {
+	'/project/:project/sequence/:sequence': {
 // 		get: [ mw.sequence.get ],
-// 		patch: [ mw.sequence.patch ],
-// 	},
+		patch: [ mw.sequence.patch ],
+	},
 //
 	'/project/:project/event/': {
 		get: [ mw.event.cache.get, mw.event.list, mw.event.cache.save ],

lib/www/server/api/middleware/sequence/index.js

@@ -1,4 +1,5 @@
 module.exports = {
 	list: require('./list'),
-	get: require('./get')
+	get: require('./get'),
+	patch: require('./patch')
 };

lib/www/server/api/middleware/sequence/patch.js

@@ -0,0 +1,17 @@
+
+const { sequence } = require('../../../lib/db');
+
+module.exports = async function (req, res, next) {
+
+	try {
+		const payload = req.body;
+
+		await sequence.patch(req.params.project, req.params.sequence, payload);
+		res.status(201).send();
+		next();
+	} catch (err) {
+		next(err);
+	}
+
+
+};

lib/www/server/lib/db/sequence/index.js

@@ -4,5 +4,6 @@ module.exports = {
 	get: require('./get'),
 	post: require('./post'),
 	put: require('./put'),
+	patch: require('./patch'),
 	delete: require('./delete')
 }

lib/www/server/lib/db/sequence/patch.js

@@ -0,0 +1,34 @@
+const { setSurvey, transaction } = require('../connection');
+
+async function patch (projectId, sequence, payload, opts = {}) {
+	const client = await setSurvey(projectId);
+
+	const patchables = {
+		"remarks": "UPDATE raw_lines SET remarks = $2 WHERE sequence = $1;",
+		"remarks_final": "UPDATE final_lines SET remarks = $2 WHERE sequence = $1;",
+		"meta": "UPDATE raw_lines SET meta = $2 WHERE sequence = $1;",
+		"meta_final": "UPDATE final_lines SET meta = $2 WHERE sequence = $1;"
+	};
+	
+	try {
+		transaction.begin(client);
+		for (const key in payload) {
+			const text = patchables[key];
+			const values = [ sequence, payload[key] ];
+			
+			if (!text) {
+				throw {status: 400, message: "Invalid patch" };
+			}
+			
+			await client.query(text, values);
+		}
+		transaction.commit(client);
+	} catch (err) {
+		transaction.rollback(err);
+		throw err;
+	} finally {
+		client.release();
+	}
+}
+
+module.exports = patch;