Check metakg before query execution and cancel on missing operations

src/index.js

@@ -8,6 +8,9 @@ const InvalidQueryGraphError = require('./exceptions/invalid_query_graph_error')
 const debug = require('debug')('bte:biothings-explorer-trapi:main');
 const Graph = require('./graph/graph');
 const EdgeManager = require('./edge_manager');
+const _ = require('lodash');
+const QEdge2BTEEdgeHandler = require('./qedge2bteedge');
+const LogEntry = require('./log_entry');
 const redisClient = require('./redis-client');
 
 exports.InvalidQueryGraphError = InvalidQueryGraphError;
@@ -108,13 +111,57 @@ exports.TRAPIQueryHandler = class TRAPIQueryHandler {
     return handler;
   }
 
+  async _edgesSupported(qEdges, kg) {
+    // _.cloneDeep() is resource-intensive but only runs once per query
+    qEdges = _.cloneDeep(qEdges);
+    const manager = new EdgeManager(qEdges);
+    const edgesMissingOps = {};
+    while (manager.getEdgesNotExecuted()) {
+      let current_edge = manager.getNext();
+      const edgeConverter = new QEdge2BTEEdgeHandler([current_edge], kg);
+      const sAPIEdges = edgeConverter.getSmartAPIEdges(current_edge);
+      if (!sAPIEdges.length) {
+        edgesMissingOps[current_edge.qEdge.id] = current_edge.reverse;
+      }
+      // assume results so next edge may be reversed or not
+      current_edge.executed = true;
+      current_edge.object.entity_count = 1;
+      current_edge.subject.entity_count = 1;
+      // this.logs = [...this.logs, ...edgeConverter.logs];
+    }
+
+    const len = Object.keys(edgesMissingOps).length;
+    // this.logs = [...this.logs, ...manager.logs];
+    let edgesToLog = Object.entries(edgesMissingOps).map(([edge, reversed]) => {
+      return reversed
+        ? `(reversed ${edge})`
+        : `(${edge})`;
+    });
+    edgesToLog = edgesToLog.length > 1
+      ? `[${edgesToLog.join(', ')}]`
+      : `${edgesToLog.join(', ')}`
+    if (len > 0) {
+      const terminateLog = `Query Edge${len > 1 ? 's' : ''} ${edgesToLog} ${
+        len > 1 ? 'have' : 'has'
+      } no SmartAPI edges. Your query terminates.`;
+      debug(terminateLog);
+      this.logs.push(new LogEntry('WARNING', null, terminateLog).getLog());
+      return false;
+    } else {
+      return true;
+    }
+  }
+
   async query() {
     this._initializeResponse();
     debug('Start to load metakg.');
     const kg = this._loadMetaKG(this.smartapiID, this.team);
     debug('MetaKG successfully loaded!');
     let queryEdges = await this._processQueryGraph(this.queryGraph);
     debug(`(3) All edges created ${JSON.stringify(queryEdges)}`);
+    if (!(await this._edgesSupported(queryEdges, kg))) {
+      return;
+    }
     const manager = new EdgeManager(queryEdges);
     while (manager.getEdgesNotExecuted()) {
       //next available/most efficient edge

src/qedge2bteedge.js

@@ -31,7 +31,7 @@ module.exports = class QEdge2BTEEdgeHandler {
    * @param {object} kg - SmartAPI Knowledge Graph Object
    * @param {object} qEdge - TRAPI Query Edge Object
    */
-  _getSmartAPIEdges(qEdge, kg = this.kg) {
+  getSmartAPIEdges(qEdge, kg = this.kg) {
     debug(`Subject node is ${qEdge.getSubject().id}`);
     debug(`Object node is ${qEdge.getObject().id}`);
     this.logs.push(
@@ -319,7 +319,7 @@ module.exports = class QEdge2BTEEdgeHandler {
   async convert(qEdges) {
     let bteEdges = [];
     await Promise.all(qEdges.map(async (edge) => {
-      const smartapi_edges = await this._getSmartAPIEdges(edge);
+      const smartapi_edges = await this.getSmartAPIEdges(edge);
       const apis = _.uniq(smartapi_edges.map(api => api.association.api_name));
       debug(`${apis.length} APIs being used:`, JSON.stringify(apis));
       debug(`${smartapi_edges.length} SmartAPI edges are retrieved....`);