Changed elasticsearch body construction

- The query body has been simplified to use just the multi_match query with any filters that are passed in the query paramaters
- the over use of bool, should, and must queries was removed. This was throwing the _score result off by making elasticsearch aggregate scores in a erroneos way.
Multi_match query now has the type (best_match) explicit. More testing with over types could help improve the search results.
The name field is given the highest weight followed by the fulltext analyzed version of itself.
This change is focused on the repos index. It might be good to review the search being done with the terms index

Author: Froilan Irizarry

services/searcher/index.js

@@ -100,32 +100,22 @@ class Searcher {
     body.query("bool", "should", query);
   }
 
-  _addFullTextQuery(body, queryParams) {
-    if (queryParams.q) {
-      // need to nest `_fulltext` query as a "must"
-      let ftBody = new Bodybuilder();
-
-      ftBody.query("bool", "should", {
-        "multi_match": {
-          "query": queryParams.q,
-          "fields": [
-            "name^10",
-            "name._fulltext^10",
-            "description^4",
-            "agency.acronym^5",
-            "agency.name^5",
-            "agency.name._fulltext^5",
-            "permissions.usageType^3",
-            "tags",
-            "tags._fulltext",
-            "languages",
-            "languages._fulltext"
-          ]
-        }
-      });
-
-      body.query("bool", "must", ftBody.build("v2")["query"]);
-    }
+  _addFullTextQuery(body, searchQuery) {
+    const searchFields = [
+      "name^10",
+      "name._fulltext^5",
+      "description^2",
+      "agency.acronym",
+      "agency.name^5",
+      "agency.name._fulltext",
+      "permissions.usageType",
+      "tags^3",
+      "tags._fulltext",
+      "languages^3",
+      "languages._fulltext"
+    ];
+
+    body.query("multi_match", 'fields', searchFields, {"query": searchQuery}, {"type": "best_fields"});
   }
 
   _addStringFilter(body, field, filter) {
@@ -236,6 +226,7 @@ class Searcher {
    * @param {any} queryParams The query parameters a user is searching for
    */
   _addSortOrder(body, queryParams) {
+    body.sort('_score', queryParams['sort'] || 'desc');
     body.sort('score', 'desc');
     if(queryParams['sort']) {
       const sortValues = [];
@@ -263,19 +254,19 @@ class Searcher {
           body.sort(sortField, 'asc');
         }
       });
-    } else {
-      body.sort('_score', queryParams['sort'] || 'desc');
     }
   }
 
   _searchReposQuery(queryParams) {
     let body = new Bodybuilder();
 
+    if(queryParams.q) {
+      this._addFullTextQuery(body, queryParams.q);
+    }
     this._addFieldFilters(body, queryParams);
     this._addSizeFromParams(body, queryParams);
-    this._addIncludeExclude(body, queryParams);
-    this._addFullTextQuery(body, queryParams);
 
+    this._addIncludeExclude(body, queryParams);
     this._addSortOrder(body, queryParams);
 
     let query = body.build("v2");