Add maxDaysAgo option to queries for a specific commodity in a system

Should improve relvance of results as some of the data can be old if left unbounded  - this is not a performance improvement, just a usability improvement.

The resutls are also sorted in a more meaningful way.

README.md

@@ -249,6 +249,10 @@ Get all buy/sell orders for a commodity in a system.
 
 e.g. https://api.ardent-industry.com/v1/system/name/Sol/commodity/name/gold
 
+##### Supported query parameters
+
+* maxDaysAgo (int); default 30
+
 #### Get a list of nearby importers of a commodity
 
 Get a list of nearby places that importing a commodity close to the specified 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ardent-api",
-  "version": "4.7.0",
+  "version": "4.8.0",
   "description": "Ardent API provides access to data submitted to EDDN",
   "main": "index.js",
   "scripts": {

router/api/systems.js

@@ -182,7 +182,11 @@ module.exports = (router) => {
   })
 
   router.get('/api/v1/system/name/:systemName/commodity/name/:commodityName', async (ctx, next) => {
-    const { systemName, commodityName } = ctx.params
+    const { 
+      systemName,
+      commodityName,
+      maxDaysAgo = DEFAULT_MAX_RESULTS_AGE
+    } = ctx.params
 
     // Validate system name
     const system = await getSystemByName(systemName)
@@ -215,6 +219,8 @@ module.exports = (router) => {
         LEFT JOIN stations.stations s ON c.marketId = s.marketId
       WHERE c.systemName = @systemName
         AND c.commodityName = @commodityName
+        AND c.updatedAtDay > '${getISOTimestamp(`-${maxDaysAgo}`).split('T')[0]}'
+      ORDER BY c.stationName
       `, { systemName, commodityName })
 
     ctx.body = commodities