From df6b7eca1a766843ae41714061834564c396ce25 Mon Sep 17 00:00:00 2001
From: Alexandre Bodin <bodin.alex@gmail.com>
Date: Mon, 30 Aug 2021 18:31:09 +0200
Subject: [PATCH] Implement fields convert query params

---
 .../lib/services/entity-service/params.js     |  7 +++---
 .../core/utils/lib/convert-query-params.js    | 24 +++++++++++++++++--
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/packages/core/strapi/lib/services/entity-service/params.js b/packages/core/strapi/lib/services/entity-service/params.js
index 8d59e37f08..cedf2c489f 100644
--- a/packages/core/strapi/lib/services/entity-service/params.js
+++ b/packages/core/strapi/lib/services/entity-service/params.js
@@ -1,6 +1,5 @@
 'use strict';
 
-const _ = require('lodash');
 const { pick } = require('lodash/fp');
 
 const {
@@ -9,19 +8,19 @@ const {
   convertStartQueryParams,
   convertPopulateQueryParams,
   convertFiltersQueryParams,
+  convertFieldsQueryParams,
 } = require('@strapi/utils/lib/convert-query-params');
 
 const { contentTypes: contentTypesUtils } = require('@strapi/utils');
 
 const { PUBLISHED_AT_ATTRIBUTE } = contentTypesUtils.constants;
 
+// TODO: check invalid values / add defaults ....
 const transformParamsToQuery = (uid, params = {}) => {
   const model = strapi.getModel(uid);
 
   const query = {};
 
-  // TODO: check invalid values / add defaults ....
-
   const {
     start,
     page,
@@ -72,7 +71,7 @@ const transformParamsToQuery = (uid, params = {}) => {
   }
 
   if (fields) {
-    query.select = _.castArray(fields);
+    query.select = convertFieldsQueryParams(fields);
   }
 
   if (populate) {
diff --git a/packages/core/utils/lib/convert-query-params.js b/packages/core/utils/lib/convert-query-params.js
index 10d3640d8a..f7880ce3f1 100644
--- a/packages/core/utils/lib/convert-query-params.js
+++ b/packages/core/utils/lib/convert-query-params.js
@@ -95,7 +95,7 @@ const convertPopulateQueryParams = (populate, depth = 0) => {
   }
 
   throw new Error(
-    'Invalid populate parameter. Expected a string or an array of strings or a populate object'
+    'Invalid populate parameter. Expected a string, an array of strings or a populate object'
   );
 };
 
@@ -126,7 +126,7 @@ const convertNestedPopulate = subPopulate => {
   }
 
   if (fields) {
-    query.select = _.castArray(fields);
+    query.select = convertFieldsQueryParams(fields);
   }
 
   if (populate) {
@@ -136,6 +136,25 @@ const convertNestedPopulate = subPopulate => {
   return query;
 };
 
+const convertFieldsQueryParams = (fields, depth = 0) => {
+  if (depth === 0 && fields === '*') {
+    return undefined;
+  }
+
+  if (typeof fields === 'string') {
+    const fieldsValues = fields.split(',').map(value => _.trim(value));
+    return _.uniq(['id', ...fieldsValues]);
+  }
+
+  if (Array.isArray(fields)) {
+    // map convert
+    const fieldsValues = fields.flatMap(value => convertPopulateQueryParams(value, depth + 1));
+    return _.uniq(['id', ...fieldsValues]);
+  }
+
+  throw new Error('Invalid fields parameter. Expected a string or an array of strings');
+};
+
 // NOTE: We could validate the parameters are on existing / non private attributes
 const convertFiltersQueryParams = filters => filters;
 
@@ -162,6 +181,7 @@ module.exports = {
   convertLimitQueryParams,
   convertPopulateQueryParams,
   convertFiltersQueryParams,
+  convertFieldsQueryParams,
   VALID_REST_OPERATORS,
   QUERY_OPERATORS,
 };