Improve error tolerance; prevent over-caching. (#95)

* Improve error tolerance; prevent over-caching.

* Update SolrIndexer.ts

Author: demiankatz

api/src/services/Fedora.ts

@@ -92,6 +92,10 @@ export class Fedora {
         return data;
     }
 
+    public clearCache(pid: string): void {
+        this.cache[pid] = {};
+    }
+
     protected getCache(pid: string, key: string): string {
         if (typeof this.cache[pid] === "undefined" || typeof this.cache[pid][key] === "undefined") {
             return null;

api/src/services/MetadataExtractor.ts

@@ -19,11 +19,8 @@ class MetadataExtractor {
      * @returns  Record mapping field names to values
      */
     public extractMetadata(dc: DC): Record<string, Array<string>> {
-        if (typeof dc.children === "undefined") {
-            throw new Error("Unexpected failure: childless Dublin Core!");
-        }
         const metadata: Record<string, Array<string>> = {};
-        dc.children.forEach((field) => {
+        (dc?.children ?? []).forEach((field) => {
             if (typeof metadata[field.name] === "undefined") {
                 metadata[field.name] = [];
             }

api/src/services/SolrIndexer.ts

@@ -64,6 +64,10 @@ class SolrIndexer {
     }
 
     async indexPid(pid: string): Promise<NeedleResponse> {
+        // Empty out Fedora cache data to be sure we get the latest
+        // information while indexing.
+        // TODO: review datastream caching logic; do we need it? Is there a better way?
+        this.hierarchyCollector.fedora.clearCache(pid);
         const fedoraFields = await this.getFields(pid);
         return await this.solr.indexRecord(this.config.solrCore, fedoraFields);
     }