Add lock on readResource.

Author: RubenVerborgh

lib/ldp.js

@@ -17,6 +17,7 @@ const parse = require('./utils').parse
 const fetch = require('node-fetch')
 const { promisify } = require('util')
 const URI = require('urijs')
+const { lock } = require('proper-lockfile')
 
 const RDF_MIME_TYPES = new Set([
   'text/turtle',            // .ttl
@@ -95,11 +96,17 @@ class LDP {
   }
 
   async readResource (url) {
+    let releaseLock
     try {
       const { path } = await this.resourceMapper.mapUrlToFile({ url })
+      releaseLock = await lock(path, { retries: 10 })
       return await promisify(fs.readFile)(path, {encoding: 'utf8'})
     } catch (err) {
       throw error(err.status, err.message)
+    } finally {
+      if (releaseLock) {
+        await releaseLock()
+      }
     }
   }