diff --git a/lib/classes/external/exporter.php b/lib/classes/external/exporter.php
index 9a262815918..38c195a5964 100644
--- a/lib/classes/external/exporter.php
+++ b/lib/classes/external/exporter.php
@@ -157,7 +157,7 @@ abstract class exporter {
                 $formatparams = $this->get_format_parameters($property);
                 $format = $record->$propertyformat;
 
-                list($text, $format) = external_format_text($data->$property, $format, $formatparams['context']->id,
+                list($text, $format) = external_format_text($data->$property, $format, $formatparams['context'],
                     $formatparams['component'], $formatparams['filearea'], $formatparams['itemid'], $formatparams['options']);
 
                 $data->$property = $text;
@@ -168,11 +168,11 @@ abstract class exporter {
 
                 if (!empty($definition['multiple'])) {
                     foreach ($data->$property as $key => $value) {
-                        $data->{$property}[$key] = external_format_string($value, $formatparams['context']->id,
+                        $data->{$property}[$key] = external_format_string($value, $formatparams['context'],
                             $formatparams['striplinks'], $formatparams['options']);
                     }
                 } else {
-                    $data->$property = external_format_string($data->$property, $formatparams['context']->id,
+                    $data->$property = external_format_string($data->$property, $formatparams['context'],
                             $formatparams['striplinks'], $formatparams['options']);
                 }
             }
diff --git a/lib/externallib.php b/lib/externallib.php
index e49aaf27c82..ec42975cab1 100644
--- a/lib/externallib.php
+++ b/lib/externallib.php
@@ -896,21 +896,25 @@ function external_validate_format($format) {
  * @param string $str The string to be filtered. Should be plain text, expect
  * possibly for multilang tags.
  * @param boolean $striplinks To strip any link in the result text. Moodle 1.8 default changed from false to true! MDL-8713
- * @param int $contextid The id of the context for the string (affects filters).
+ * @param context|int $contextorid The id of the context for the string or the context (affects filters).
  * @param array $options options array/object or courseid
  * @return string text
  * @since Moodle 3.0
  */
-function external_format_string($str, $contextid, $striplinks = true, $options = array()) {
+function external_format_string($str, $contextorid, $striplinks = true, $options = array()) {
 
     // Get settings (singleton).
     $settings = external_settings::get_instance();
-    if (empty($contextid)) {
+    if (empty($contextorid)) {
         throw new coding_exception('contextid is required');
     }
 
     if (!$settings->get_raw()) {
-        $context = context::instance_by_id($contextid);
+        if (is_object($contextorid) && is_a($contextorid, 'context')) {
+            $context = $contextorid;
+        } else {
+            $context = context::instance_by_id($contextorid);
+        }
         $options['context'] = $context;
         $options['filter'] = isset($options['filter']) && !$options['filter'] ? false : $settings->get_filter();
         $str = format_string($str, $striplinks, $options);
@@ -944,7 +948,7 @@ function external_format_string($str, $contextid, $striplinks = true, $options =
  *
  * @param string $text The content that may contain ULRs in need of rewriting.
  * @param int $textformat The text format.
- * @param int $contextid This parameter and the next two identify the file area to use.
+ * @param context|int $contextorid This parameter and the next two identify the file area to use.
  * @param string $component
  * @param string $filearea helps identify the file area.
  * @param int $itemid helps identify the file area.
@@ -953,13 +957,21 @@ function external_format_string($str, $contextid, $striplinks = true, $options =
  * @since Moodle 2.3
  * @since Moodle 3.2 component, filearea and itemid are optional parameters
  */
-function external_format_text($text, $textformat, $contextid, $component = null, $filearea = null, $itemid = null,
+function external_format_text($text, $textformat, $contextorid, $component = null, $filearea = null, $itemid = null,
                                 $options = null) {
     global $CFG;
 
     // Get settings (singleton).
     $settings = external_settings::get_instance();
 
+    if (is_object($contextorid) && is_a($contextorid, 'context')) {
+        $context = $contextorid;
+        $contextid = $context->id;
+    } else {
+        $context = null;
+        $contextid = $contextorid;
+    }
+
     if ($component and $filearea and $settings->get_fileurl()) {
         require_once($CFG->libdir . "/filelib.php");
         $text = file_rewrite_pluginfile_urls($text, $settings->get_file(), $contextid, $component, $filearea, $itemid);
@@ -979,7 +991,7 @@ function external_format_text($text, $textformat, $contextid, $component = null,
 
         $options['filter'] = isset($options['filter']) && !$options['filter'] ? false : $settings->get_filter();
         $options['para'] = isset($options['para']) ? $options['para'] : false;
-        $options['context'] = context::instance_by_id($contextid);
+        $options['context'] = !is_null($context) ? $context : context::instance_by_id($contextid);
         $options['allowid'] = isset($options['allowid']) ? $options['allowid'] : true;
 
         $text = format_text($text, $textformat, $options);
diff --git a/lib/tests/externallib_test.php b/lib/tests/externallib_test.php
index 5d449da04d0..2f1aaf640ab 100644
--- a/lib/tests/externallib_test.php
+++ b/lib/tests/externallib_test.php
@@ -128,7 +128,9 @@ class core_externallib_testcase extends advanced_testcase {
         $test = '$$ \pi $$';
         $testformat = FORMAT_MARKDOWN;
         $correct = array($test, $testformat);
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0), $correct);
 
         $settings->set_raw(false);
         $settings->set_filter(true);
@@ -137,48 +139,62 @@ class core_externallib_testcase extends advanced_testcase {
         $testformat = FORMAT_MARKDOWN;
         $correct = array('<span class="filter_mathjaxloader_equation"><p><span class="nolink">$$ \pi $$</span></p>
 </span>', FORMAT_HTML);
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0), $correct);
 
         // Filters can be opted out from by the developer.
         $test = '$$ \pi $$';
         $testformat = FORMAT_MARKDOWN;
         $correct = array('<p>$$ \pi $$</p>
 ', FORMAT_HTML);
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0, ['filter' => false]), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0, ['filter' => false]), $correct);
 
         $test = '<p><a id="test"></a><a href="#test">Text</a></p>';
         $testformat = FORMAT_HTML;
         $correct = array($test, FORMAT_HTML);
         $options = array('allowid' => true);
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0, $options), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0, $options), $correct);
 
         $test = '<p><a id="test"></a><a href="#test">Text</a></p>';
         $testformat = FORMAT_HTML;
         $correct = array('<p><a></a><a href="#test">Text</a></p>', FORMAT_HTML);
         $options = new StdClass();
         $options->allowid = false;
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0, $options), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0, $options), $correct);
 
         $test = '<p><a id="test"></a><a href="#test">Text</a></p>'."\n".'Newline';
         $testformat = FORMAT_MOODLE;
         $correct = array('<p><a id="test"></a><a href="#test">Text</a></p> Newline', FORMAT_HTML);
         $options = new StdClass();
         $options->newlines = false;
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0, $options), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0, $options), $correct);
 
         $test = '<p><a id="test"></a><a href="#test">Text</a></p>';
         $testformat = FORMAT_MOODLE;
         $correct = array('<div class="text_to_html">'.$test.'</div>', FORMAT_HTML);
         $options = new StdClass();
         $options->para = true;
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0, $options), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0, $options), $correct);
 
         $test = '<p><a id="test"></a><a href="#test">Text</a></p>';
         $testformat = FORMAT_MOODLE;
         $correct = array($test, FORMAT_HTML);
         $options = new StdClass();
         $options->context = $context;
+        // Function external_format_text should work with context id or context instance.
         $this->assertSame(external_format_text($test, $testformat, $context->id, 'core', '', 0, $options), $correct);
+        $this->assertSame(external_format_text($test, $testformat, $context, 'core', '', 0, $options), $correct);
 
         $settings->set_raw($currentraw);
         $settings->set_filter($currentfilter);
@@ -203,7 +219,9 @@ class core_externallib_testcase extends advanced_testcase {
         $test = '<span lang="en" class="multilang">EN</span><span lang="fr" class="multilang">FR</span> ' .
             '<script>hi</script> <h3>there</h3>!';
         $correct = $test;
+        // Function external_format_string should work with context id or context instance.
         $this->assertSame($correct, external_format_string($test, $context->id));
+        $this->assertSame($correct, external_format_string($test, $context));
 
         $settings->set_raw(false);
         $settings->set_filter(false);
@@ -211,20 +229,26 @@ class core_externallib_testcase extends advanced_testcase {
         $test = '<span lang="en" class="multilang">EN</span><span lang="fr" class="multilang">FR</span> ' .
             '<script>hi</script> <h3>there</h3>?';
         $correct = 'ENFR hi there?';
+        // Function external_format_string should work with context id or context instance.
         $this->assertSame($correct, external_format_string($test, $context->id));
+        $this->assertSame($correct, external_format_string($test, $context));
 
         $settings->set_filter(true);
 
         $test = '<span lang="en" class="multilang">EN</span><span lang="fr" class="multilang">FR</span> ' .
             '<script>hi</script> <h3>there</h3>@';
         $correct = 'EN hi there@';
+        // Function external_format_string should work with context id or context instance.
         $this->assertSame($correct, external_format_string($test, $context->id));
+        $this->assertSame($correct, external_format_string($test, $context));
 
         // Filters can be opted out.
         $test = '<span lang="en" class="multilang">EN</span><span lang="fr" class="multilang">FR</span> ' .
             '<script>hi</script> <h3>there</h3>%';
         $correct = 'ENFR hi there%';
+        // Function external_format_string should work with context id or context instance.
         $this->assertSame($correct, external_format_string($test, $context->id, false, ['filter' => false]));
+        $this->assertSame($correct, external_format_string($test, $context, false, ['filter' => false]));
 
         $this->assertSame("& < > \" '", format_string("& < > \" '", true, ['escape' => false]));