Common Pitfalls When Implementing Ajax Search In WordPress
Slow Page Load Times
Querying the entire WordPress database on every search can overwork the server and drastically increase page load times. This strains server resources and provides a poor user experience. To optimize performance, implement caching mechanisms to serve recent searches quickly. Also restrict search queries to only index post titles and excerpts rather than full post content. Indexing less data speeds up search response while still providing relevant results.
Caching Search Results
A common technique is to cache search results in the WordPress object cache for a set time period. This avoids hitting the database on recurring queries. For example, when a visitor searches “resizable image plugin”, the first query will hit the database and return posts. Subsequent searches for “resizable image plugin” within 5 minutes could show the cached results instead of querying the database again. This significantly reduces server load.
Searching Limited Content
Rather than indexing full post content which requires heavy processing, only search titles, excerpts, tags and categories. Visitors typically determine relevance from titles and brief descriptions rather than full post content. Limiting search to critical metadata speeds response time while delivering pertinent search returns.
Inconsistent User Experience
Allowing unstructured search queries yields irrelevant, confusing search returns that frustrate users. For example, vague queries like “best plugin” are unclear. Instead, filter search inputs to refine intent. Only search post titles and excerpts for an exact phrase match or subsets of keywords. This presents visitors with precisely matching results catered to their initial search phrase without unrelated returns. Implement JavaScript validation on search inputs to refine queries prior to searching.
Search Filtering
Filter search queries to only titles, excerpts, tags and categories rather than all post fields. This avoids wide irrelevant results. Also only return posts rather than custom post types like pages or products. Visitors expect relevant blog post returns from search. Focus the scope on critical post data to deliver an expected experience.
Validating Inputs with JavaScript
Use JavaScript to process search inputs prior to querying. Check query length and reject short vague terms. Also programmatically append modifiers to refine search returns. If a user searches “plugin” redirect the back end query to search for “WordPress plugin” instead. This forces precise relevancy without changing the user experience.
Accessibility Issues
Relying solely on AJAX requests for search limits accessibility for those requiring assistive tools like screen readers. Also, JavaScript fails to execute on a portion of devices. To expand accessibility, build the experience to gracefully degrade without JavaScript. Show basic HTML search forms and results sans JavaScript. Then enhance visually with AJAX rather than depending completely on it. Supporting both scenarios ensures accessibility.
Progressive Enhancement
Stick to progressive enhancement principles by serving basic HTML first. Display a standard search form, then use JavaScript to send queries asynchronously and update the page with results inline. If JavaScript fails, users still get a functional experience. Design for failure scenarios via progressive enhancement.
Accessible Fallback Content
When JavaScript runs on a page, hide the basic HTML markup rather than removing it. If AJAX fails, reveal the HTML content again. This provides accessible fallback content for screen readers, text browsers and deprecated devices. Do not rely on AJAX alone. Build in a baseline experience, then enhance for capable clients.
Lack of Security Precautions
AJAX opens up cross-site scripting vulnerabilities if not properly handled. Malicious code can execute JS remotely. Thus its critical to escape all inputs and outputs. Escape user search queries to prevent code execution both client and server side. Doing so protects the app from destructive requests while maintaining dynamic functionality.
Server Side Validation
In addition to client side preparation, validate search parameters server side too prior to querying. Check nothing potentially dangerous was missed client side by scanning server side too. Look for red flags indicating malicious searches before running queries. Never trust client side alone.
Database Query Parameterization
Beyond escaping search strings, parameterize database queries to avoid code running as part of the search parameter values. Separate out user inputs from queries through parameters to prevent custom code ending up in query strings.
Difficulty with Styling & Markup
Dynamically updating HTML via JS often generates improperly structured markup leading to display issues. Instead, register custom hooks to inject valid HTML search forms and results generated from PHP. This keeps HTML valid while preventing complicated JS markup generation.
Dedicated Hooks
Register AJAX scripts only on certain pages through custom hooks rather than site wide. Limit scripts and styles to exclusively search result pages and forms vs globally. Then hook structured HTML markup into those specific pages only. Containing AJAX enables easier debugging and better performance.
Using a Wrapper
Wrap AJAX search forms and results in a container element. Scope style rules only to that container vs page wide styles. Then generate valid semantic HTML search markup via PHP hooked inside that wrapper area. This encapsulates styling and structure changes.
Dependencies on Plugins/Frameworks
Some AJAX implementations depend too heavily on external libraries and components. This hinders debugging, increases bloat and inhibits custom enhancements. Rather than third party tie ins, take an object-oriented design approach building out reusable search classes. Minimize dependencies while compartmentalizing functionality for easier long term management.
Custom Search Classes
Break search functionality into distinct class files separating concerns into dedicated classes with single responsibilities. For example, classes for search mechanics, result display, caching, query preparation etc. Then instantiate class objects only when needed rather than loading dependencies globally.
Limiting Third Party Code
Avoid relying on third party JavaScript code for AJAX handling and DOM manipulation. Take advantage of native browser Fetch API support to handle AJAX requests instead of library dependencies. Similarly, use vanilla JavaScript for displaying results rather than heavy frameworks or libraries.
Testing & Browser Compatibility
Being JavaScript reliant, AJAX experiences require thorough testing across browsers and devices to uncover compatibility issues. Manually testing all scenarios is time prohibitive. Instead take an automated testing approach using frameworks like Jest, Mocha and Chai for rapid feedback across environments.
Automated Testing Suite
Build out a testing suite covering critical user flows like search submissions, caching, query preparation etc. Execute these automatted suite frequently against a matrix of browsers during development. This consistent automated feedback cycle surfaces problems early before users ever encounter them.
Continuous Integration
Take automated testing farther by implementing continuous integration pipelines. Services like Travis CI can clone repos, run test suites against multiple environments and report feedback on every commit. Configure CI services to capture bugs with every incremental code change enabling rapid repairs.
