Function readGraph

lib/handlers/patch.mjs:113–144

(resource)

// Reads the RDF graph in the given resource
function readGraph (resource) {
  // Read the resource's file
  return new Promise((resolve, reject) =>
    fs.readFile(resource.path, { encoding: 'utf8' }, function (err, fileContents) {
      if (err) {
        // If the file does not exist, assume empty contents
        // (it will be created after a successful patch)
        if (err.code === 'ENOENT') {
          fileContents = contentForNew(resource.contentType)
          // Fail on all other errors
        } else {
          return reject(error(500, `Original file read error: ${err}`))
        }
      }
      debug('PATCH -- Read target file (%d bytes)', fileContents.length)
      fileContents = resource.contentType.includes('json') ? JSON.parse(fileContents) : fileContents
      resolve(fileContents)
    })
  )
  // Parse the resource's file contents
    .then((fileContents) => {
      const graph = $rdf.graph()
      debug('PATCH -- Reading %s with content type %s', resource.url, resource.contentType)
      try {
        $rdf.parse(fileContents, graph, resource.url, resource.contentType)
      } catch (err) {
        throw error(500, `Patch: Target ${resource.contentType} file syntax error: ${err}`)
      }
      debug('PATCH -- Parsed target file')
      return graph
    })
}

// Verifies whether the user is allowed to perform the patch on the target
async function checkPermission (request, patchObject, resourceExists) {