#911 fix streaming sort (#912)

#911 fix streaming sort.

build.gradle

@@ -40,7 +40,7 @@ repositories {
 }
 
 group = 'au.org.ala'
-version = '3.5.0-SNAPSHOT'
+version = '3.5.1-SNAPSHOT'
 
 
 boolean inplace = false

src/main/java/au/org/ala/biocache/dao/SolrIndexDAOImpl.java

@@ -1175,17 +1175,39 @@ private ModifiableSolrParams buildSearchExpr(SolrQuery query) {
  }
  }
  }
+
  if (StringUtils.isNotEmpty(query.getFields())) {
  solrParams.set("fl", StringUtils.join(fieldMappingUtil.translateFieldArray(query.getFields().split(",")), ","));
  } else {
  solrParams.set("fl", "id");
  }
 
- // The sort field does not need to be present in the field list.
- if (StringUtils.isEmpty(query.getSortField())) {
- solrParams.set("sort", "id asc");
- } else {
+ // The sort field is required, sometimes. Testing suggests that this depends on the solrClient class.
+ // 1. use the query specified sort, without checking if it is in the list of fields
+ // 2. use the first non-multivalue field
+ // 3. use "id asc" and append "id" to the fl if it is missing
+ //
+ // Handle the error for some solrClient classes when the default query sort is "score asc" by excluding it
+ if (StringUtils.isNotEmpty(query.getSortField()) && !"score asc".equals(query.getSortField())) {
  solrParams.set("sort", query.getSortField());
+ } else {
+ String [] fl = solrParams.get("fl").split(",");
+ String nonMultivalueField = null;
+ for (String field : fl) {
+ IndexFieldDTO f = indexFieldMap.get(field);
+ if (f != null && !f.isMultivalue()) {
+ nonMultivalueField = f.getName();
+ break;
+ }
+ }
+ if (nonMultivalueField != null) {
+ solrParams.set("sort", nonMultivalueField + " asc");
+ } else {
+ solrParams.set("sort", "id asc");
+
+ // append "id" to field list
+ solrParams.set("fl", solrParams.get("fl") + ",id");
+ }
  }
 
  String qt = "/export";