{"id":1248,"date":"2023-07-27T05:00:00","date_gmt":"2023-07-27T12:00:00","guid":{"rendered":"https:\/\/www.angulartraining.com\/daily-newsletter\/?p=1248"},"modified":"2023-07-26T10:55:21","modified_gmt":"2023-07-26T17:55:21","slug":"how-to-use-http-interceptors","status":"publish","type":"post","link":"https:\/\/www.angulartraining.com\/daily-newsletter\/how-to-use-http-interceptors\/","title":{"rendered":"How to use HTTP interceptors?"},"content":{"rendered":"\n<p>Angular <a href=\"https:\/\/angular.io\/api\/common\/http\/HttpInterceptor\" target=\"_blank\" rel=\"noopener\" title=\"\">HTTP interceptors<\/a> can intercept and modify HTTP requests and responses. They can be used for a variety of purposes, such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Logging<\/strong> the details of HTTP requests and responses, such as the URL, headers, and body. This can be helpful for debugging and troubleshooting.<\/li>\n\n\n\n<li><strong>Authentication<\/strong>: Authenticate requests before they are sent to the server by adding custom headers to the HTTP request.<\/li>\n\n\n\n<li><strong>Caching<\/strong>: Interceptors can be used to cache HTTP responses, improving performance.<\/li>\n\n\n\n<li><strong>Error handling<\/strong>: Handle errors that occur during HTTP requests. This can help provide feedback to the user when the connection with the server is lost.<\/li>\n<\/ul>\n\n\n\n<p>To create an Angular HTTP interceptor, you must create a class that implements the <code>HttpInterceptor<\/code> interface. The <code>intercept()<\/code> method of this interface is called whenever an HTTP request is made. <\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"904\" height=\"127\" src=\"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-39.png\" alt=\"\" class=\"wp-image-1249\" srcset=\"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-39.png 904w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-39-300x42.png 300w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-39-768x108.png 768w\" sizes=\"auto, (max-width: 904px) 100vw, 904px\" \/><\/figure>\n\n\n\n<p><\/p>\n\n\n\n<p>This method allows you to inspect and modify the request before sending it to the server.<\/p>\n\n\n\n<p>Here is an example of an Angular HTTP interceptor that logs the details of HTTP requests:<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"488\" src=\"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-40-1024x488.png\" alt=\"\" class=\"wp-image-1250\" srcset=\"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-40-1024x488.png 1024w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-40-300x143.png 300w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-40-768x366.png 768w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-40-1536x731.png 1536w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-40.png 1714w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p><\/p>\n\n\n\n<p>To use an Angular HTTP interceptor, you need to register it. You can do this by adding the interceptor to the <code>providers<\/code> array of your <code>AppModule<\/code> as follows:<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"488\" src=\"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-41-1024x488.png\" alt=\"\" class=\"wp-image-1251\" srcset=\"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-41-1024x488.png 1024w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-41-300x143.png 300w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-41-768x366.png 768w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-41-1536x731.png 1536w, https:\/\/www.angulartraining.com\/daily-newsletter\/wp-content\/uploads\/2023\/07\/image-41.png 1714w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p><\/p>\n\n\n\n<p>Once you have registered an HTTP interceptor, it will be called whenever an HTTP request is made.<\/p>\n\n\n\n<p>You can see a complete example of <a href=\"https:\/\/blog.angulartraining.com\/http-interceptors-in-angular-61dcf80b6bdd\" target=\"_blank\" rel=\"noopener\" title=\"\">how to intercept a request to add an auth token in this tutorial<\/a>. The tutorial also covers how to intercept a response and change it. A complete<a href=\"https:\/\/stackblitz.com\/edit\/at-http-interceptor-format?file=src%2Fapp%2Ftoken-http-interceptor.service.ts\" target=\"_blank\" rel=\"noopener\" title=\"\"> example<\/a> of such an interceptor can be found on <a href=\"https:\/\/stackblitz.com\/edit\/at-http-interceptor-format?file=src%2Fapp%2Ftoken-http-interceptor.service.ts\" target=\"_blank\" rel=\"noopener\" title=\"\">Stackblitz<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Angular HTTP interceptors can intercept and modify HTTP requests and responses. They can be used for a variety of purposes, such as: To create an Angular HTTP interceptor, you must create a class that implements the HttpInterceptor interface. The intercept() method of this interface is called whenever an HTTP request is made. This method allows [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,32],"tags":[],"class_list":["post-1248","post","type-post","status-publish","format-standard","hentry","category-angular","category-http"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/posts\/1248","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/comments?post=1248"}],"version-history":[{"count":3,"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/posts\/1248\/revisions"}],"predecessor-version":[{"id":1254,"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/posts\/1248\/revisions\/1254"}],"wp:attachment":[{"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/media?parent=1248"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/categories?post=1248"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.angulartraining.com\/daily-newsletter\/wp-json\/wp\/v2\/tags?post=1248"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}