{"id":5872,"date":"2021-07-10T12:29:23","date_gmt":"2021-07-10T06:59:23","guid":{"rendered":"https:\/\/golangbyexamples.com\/?p=5872"},"modified":"2021-07-10T16:49:56","modified_gmt":"2021-07-10T11:19:56","slug":"400-http-status-response-golang","status":"publish","type":"post","link":"https:\/\/golangbyexamples.com\/400-http-status-response-golang\/","title":{"rendered":"Return 400 (Bad Request) Status Code in http response in Go (Golang)"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_17 counter-hierarchy counter-decimal ez-toc-light-blue\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" style=\"display: none;\"><i class=\"ez-toc-glyphicon ez-toc-icon-toggle\"><\/i><\/a><\/span><\/div>\n<nav><ul class=\"ez-toc-list ez-toc-list-level-1\"><li class=\"ez-toc-page-1 ez-toc-heading-level-2\"><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/golangbyexamples.com\/400-http-status-response-golang\/#Overview\" title=\"Overview\">Overview<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-2\"><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/golangbyexamples.com\/400-http-status-response-golang\/#Program\" title=\"Program\">Program<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"has-luminous-vivid-orange-color has-text-color wp-block-heading\"><span class=\"ez-toc-section\" id=\"Overview\"><\/span><strong>Overview<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"has-medium-font-size\"><strong>net\/http<\/strong> package of golang provides the status code constants which could be used to return different status codes- <a href=\"https:\/\/golang.org\/src\/net\/http\/status.go\">https:\/\/golang.org\/src\/net\/http\/status.go<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size\">The same can also be used to return the 400 (Bad Request) HTTP status code.&nbsp; The HTTP 400 status code is defined by the below constant<\/p>\n\n\n\n<p class=\"has-medium-font-size\">In this article, we will also see how to return a JSON body along with the 400 (Bad Request) Status Code<\/p>\n\n\n\n<h2 class=\"has-luminous-vivid-orange-color has-text-color wp-block-heading\"><span class=\"ez-toc-section\" id=\"Program\"><\/span><strong>Program<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"has-medium-font-size\">Below is the program for the same<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nimport (\n\t\"net\/http\"\n)\n\nfunc main() {\n\thandler := http.HandlerFunc(handleRequest)\n\thttp.Handle(\"\/example\", handler)\n\thttp.ListenAndServe(\":8080\", nil)\n}\n\nfunc handleRequest(w http.ResponseWriter, r *http.Request) {\n\tw.WriteHeader(http.StatusBadRequest)\n\treturn\n}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Here we are using the <strong>WriteHeader<\/strong> function to specify the http status code<\/p>\n\n\n\n<p class=\"has-medium-font-size\">Run the above program. It will start a server on 8080 port on your local machine. Now make the below curl call to the server<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">curl -v -X POST http:\/\/localhost:8080\/example<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Below will be the output<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">* Connected to localhost (::1) port 8080 (#0)\n> POST \/example HTTP\/1.1\n> Host: localhost:8080\n> User-Agent: curl\/7.54.0\n> Accept: *\/*\n> \n< HTTP\/1.1 400 Bad Request\n< Date: Sat, 10 Jul 2021 05:50:32 GMT\n< Content-Length: 0\n< \n* Connection #0 to host localhost left intact<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">As you can see from the output, it will correctly return the 400 status code. If we also want to return the JSON error body, then below is the code for the same<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nimport (\n\t\"encoding\/json\"\n\t\"log\"\n\t\"net\/http\"\n)\n\nfunc main() {\n\thandler := http.HandlerFunc(handleRequest)\n\thttp.Handle(\"\/example\", handler)\n\thttp.ListenAndServe(\":8080\", nil)\n}\n\nfunc handleRequest(w http.ResponseWriter, r *http.Request) {\n\tw.WriteHeader(http.StatusBadRequest)\n\tw.Header().Set(\"Content-Type\", \"application\/json\")\n\tresp := make(map[string]string)\n\tresp[\"message\"] = \"Bad Request\"\n\tjsonResp, err := json.Marshal(resp)\n\tif err != nil {\n\t\tlog.Fatalf(\"Error happened in JSON marshal. Err: %s\", err)\n\t}\n\tw.Write(jsonResp)\n\treturn\n}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">The above code returns the below JSON request body back in response<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">{\"message\":\"Bad Request\"}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Run the above program. It will start a server on 8080 port on your local machine. Now make the below curl call to the server<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">curl -v -X POST http:\/\/localhost:8080\/example<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Below will be the output<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">* Connected to localhost (::1) port 8080 (#0)\n> POST \/example HTTP\/1.1\n> Host: localhost:8080\n> User-Agent: curl\/7.54.0\n> Accept: *\/*\n> \n< HTTP\/1.1 400 Bad Request\n< Date: Sat, 10 Jul 2021 05:58:42 GMT\n< Content-Length: 25\n< Content-Type: text\/plain; charset=utf-8\n< \n* Connection #0 to host localhost left intact\n{\"message\":\"Bad Request\"}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">As you can see from the output, it correctly returns the 400 status code along with the body.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">You can also directly pass 400 to the WriteHeader function to send the 400 response.<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">w.WriteHeader(400)<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">This also works correctly. Try it out.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">Also, check out our Golang advance tutorial Series - <a href=\"https:\/\/golangbyexamples.com\/golang-comprehensive-tutorial\/\">Golang Advance Tutorial<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Table of Contents OverviewProgram Overview net\/http package of golang provides the status code constants which could be used to return different status codes- https:\/\/golang.org\/src\/net\/http\/status.go The same can also be used to return&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false},"categories":[1],"tags":[331,3,4],"class_list":["post-5872","post","type-post","status-publish","format-standard","hentry","category-tech","tag-331","tag-go","tag-golang"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.7 - 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