Highlighting the elastic search giving the results only matched - php

Question

Working on Php and Elastic Search 6.5.2. For test scenario I used postman, When I apply Highlighting, Only the trimmed piece of content which has matched keyword sentence is displaying when I added two or more fragments under the highlight. I Don't wan to trim the content at the elastic search level. For this I changed the number of fragments to zero and I got the expected output in the elastic search that its giving the whole content, butwhen I check the output in the php application the whole content is getting bold whenever the matched keyword existing in the url field.
Index:
PUT test/_doc/1
{
"title":"Apply For the admissions graduate and undergraduate"
"url":"https://someurl.com/admissions",
"content": "Engineers play an important role in almost every aspect of modern life. As an engineer in the 21st century, you’ll work in teams to develop ingenious ways to transform the world in which we live. Industrial engineers are in high demand in nearly every industry. Astounding innovations in semiconductor microelectronic engineering will continue to drive productivity and the economy by playing a key role in a wide range of technologies – information, communication, nanotechnology, defense, medicine, and energy.Admission into the microelectronic engineering program is competitive, but our admission process is a personal one. Each application is reviewed holistically for strength of academic preparation, performance on standardized tests, counselor recommendations, and your personal career interests. We seek applicants from a variety of geographical, social, cultural, economic, and ethnic backgrounds."
}
Query:
{
"query":{
"query_string":{
"fields":[
"content"
],
"query":"admissions"
}
},
"highlight":{
"fields":{
"title":{
"pre_tags":[
"<strong>"
],
"post_tags":[
"</strong>"
],
"number_of_fragments":3 //changed to 0 earlier
},
"content":{
"pre_tags":[
"<strong>"
],
"post_tags":[
"</strong>"
],
"fragment_size":150,
"number_of_fragments":3 //changed to 0 earlier
}
}
}
}
Result:
"highlight": {
"content": [
"information, communication, nanotechnology, defense, medicine, and energy.Admission into the microelectronic engineering program is competitive, but our <strong>admission</strong>"
]
}

Answer 1

After looking at the code you shared via comments. This issue is not in elasticsearch response.
This following line is causing the issue:
<?php echo substr($r['highlight']['content'][0],0,300); ?>
Due to this one of the result is missing closing </b> tag as you are taking only first 300 characters.
If you notice you can see, one of the highlighting content in your html has the following:
Tourism Management Curriculum Capstone/Exam/Thesis Options <b>Admissi</div>
As you can see closing </b> tag is missing for <b>Admissi and hence everything after this is in bold.
Solution to this could be not using substring.