2020-03-10 15:01:52 +00:00
<!DOCTYPE HTML>
< html lang = "" >
< head >
< meta charset = "UTF-8" >
< meta content = "text/html; charset=utf-8" http-equiv = "Content-Type" >
< title > Exception Handling with Ring · GitBook< / title >
< meta http-equiv = "X-UA-Compatible" content = "IE=edge" / >
< meta name = "description" content = "" >
< meta name = "generator" content = "GitBook 3.2.3" >
< link rel = "stylesheet" href = "../gitbook/style.css" >
< link rel = "stylesheet" href = "../gitbook/gitbook-plugin-hints/plugin-hints.css" >
< link rel = "stylesheet" href = "../gitbook/gitbook-plugin-highlight/website.css" >
< link rel = "stylesheet" href = "../gitbook/gitbook-plugin-search/search.css" >
< link rel = "stylesheet" href = "../gitbook/gitbook-plugin-fontsettings/website.css" >
< meta name = "HandheldFriendly" content = "true" / >
< meta name = "viewport" content = "width=device-width, initial-scale=1, user-scalable=no" >
< meta name = "apple-mobile-web-app-capable" content = "yes" >
< meta name = "apple-mobile-web-app-status-bar-style" content = "black" >
< link rel = "apple-touch-icon-precomposed" sizes = "152x152" href = "../gitbook/images/apple-touch-icon-precomposed-152.png" >
< link rel = "shortcut icon" href = "../gitbook/images/favicon.ico" type = "image/x-icon" >
< link rel = "next" href = "default_middleware.html" / >
< link rel = "prev" href = "middleware_registry.html" / >
< / head >
< body >
< div class = "book" >
< div class = "book-summary" >
< div id = "book-search-input" role = "search" >
< input type = "text" placeholder = "Type to search" / >
< / div >
< nav role = "navigation" >
< ul class = "summary" >
< li class = "header" > Introduction< / li >
< li class = "chapter " data-level = "1.1" data-path = "../" >
< a href = "../" >
Introduction
< / a >
< / li >
< li class = "header" > Basics< / li >
< li class = "chapter " data-level = "2.1" data-path = "../basics/route_syntax.html" >
< a href = "../basics/route_syntax.html" >
Route Syntax
< / a >
< / li >
< li class = "chapter " data-level = "2.2" data-path = "../basics/router.html" >
< a href = "../basics/router.html" >
Router
< / a >
< / li >
< li class = "chapter " data-level = "2.3" data-path = "../basics/path_based_routing.html" >
< a href = "../basics/path_based_routing.html" >
Path-based Routing
< / a >
< / li >
< li class = "chapter " data-level = "2.4" data-path = "../basics/name_based_routing.html" >
< a href = "../basics/name_based_routing.html" >
Name-based Routing
< / a >
< / li >
< li class = "chapter " data-level = "2.5" data-path = "../basics/route_data.html" >
< a href = "../basics/route_data.html" >
Route Data
< / a >
< / li >
< li class = "chapter " data-level = "2.6" data-path = "../basics/route_data_validation.html" >
< a href = "../basics/route_data_validation.html" >
Route Data Validation
< / a >
< / li >
< li class = "chapter " data-level = "2.7" data-path = "../basics/route_conflicts.html" >
< a href = "../basics/route_conflicts.html" >
Route Conflicts
< / a >
< / li >
< li class = "chapter " data-level = "2.8" data-path = "../basics/error_messages.html" >
< a href = "../basics/error_messages.html" >
Error Messages
< / a >
< / li >
< li class = "header" > Coercion< / li >
< li class = "chapter " data-level = "3.1" data-path = "../coercion/coercion.html" >
< a href = "../coercion/coercion.html" >
Coercion Explained
< / a >
< / li >
< li class = "chapter " data-level = "3.2" data-path = "../coercion/schema_coercion.html" >
< a href = "../coercion/schema_coercion.html" >
Plumatic Schema
< / a >
< / li >
< li class = "chapter " data-level = "3.3" data-path = "../coercion/clojure_spec_coercion.html" >
< a href = "../coercion/clojure_spec_coercion.html" >
Clojure.spec
< / a >
< / li >
< li class = "chapter " data-level = "3.4" data-path = "../coercion/data_spec_coercion.html" >
< a href = "../coercion/data_spec_coercion.html" >
Data-specs
< / a >
< / li >
< li class = "header" > Ring< / li >
< li class = "chapter " data-level = "4.1" data-path = "ring.html" >
< a href = "ring.html" >
Ring-router
< / a >
< / li >
< li class = "chapter " data-level = "4.2" data-path = "reverse_routing.html" >
< a href = "reverse_routing.html" >
Reverse-routing
< / a >
< / li >
< li class = "chapter " data-level = "4.3" data-path = "default_handler.html" >
< a href = "default_handler.html" >
Default handler
< / a >
< / li >
< li class = "chapter " data-level = "4.4" data-path = "slash_handler.html" >
< a href = "slash_handler.html" >
Slash handler
< / a >
< / li >
< li class = "chapter " data-level = "4.5" data-path = "static.html" >
< a href = "static.html" >
Static Resources
< / a >
< / li >
< li class = "chapter " data-level = "4.6" data-path = "dynamic_extensions.html" >
< a href = "dynamic_extensions.html" >
Dynamic Extensions
< / a >
< / li >
< li class = "chapter " data-level = "4.7" data-path = "data_driven_middleware.html" >
< a href = "data_driven_middleware.html" >
Data-driven Middleware
< / a >
< / li >
< li class = "chapter " data-level = "4.8" data-path = "transforming_middleware_chain.html" >
< a href = "transforming_middleware_chain.html" >
Transforming Middleware Chain
< / a >
< / li >
< li class = "chapter " data-level = "4.9" data-path = "middleware_registry.html" >
< a href = "middleware_registry.html" >
Middleware Registry
< / a >
< / li >
< li class = "chapter active" data-level = "4.10" data-path = "exceptions.html" >
< a href = "exceptions.html" >
Exception Handling with Ring
< / a >
< / li >
< li class = "chapter " data-level = "4.11" data-path = "default_middleware.html" >
< a href = "default_middleware.html" >
Default Middleware
< / a >
< / li >
< li class = "chapter " data-level = "4.12" data-path = "content_negotiation.html" >
< a href = "content_negotiation.html" >
Content Negotiation
< / a >
< / li >
< li class = "chapter " data-level = "4.13" data-path = "coercion.html" >
< a href = "coercion.html" >
Pluggable Coercion
< / a >
< / li >
< li class = "chapter " data-level = "4.14" data-path = "route_data_validation.html" >
< a href = "route_data_validation.html" >
Route Data Validation
< / a >
< / li >
< li class = "chapter " data-level = "4.15" data-path = "compiling_middleware.html" >
< a href = "compiling_middleware.html" >
Compiling Middleware
< / a >
< / li >
< li class = "chapter " data-level = "4.16" data-path = "swagger.html" >
< a href = "swagger.html" >
Swagger Support
< / a >
< / li >
< li class = "chapter " data-level = "4.17" data-path = "RESTful_form_methods.html" >
< a href = "RESTful_form_methods.html" >
RESTful form methods
< / a >
< / li >
< li class = "header" > HTTP< / li >
< li class = "chapter " data-level = "5.1" data-path = "../http/interceptors.html" >
< a href = "../http/interceptors.html" >
Interceptors
< / a >
< / li >
< li class = "chapter " data-level = "5.2" data-path = "../http/pedestal.html" >
< a href = "../http/pedestal.html" >
Pedestal
< / a >
< / li >
< li class = "chapter " data-level = "5.3" data-path = "../http/sieppari.html" >
< a href = "../http/sieppari.html" >
Sieppari
< / a >
< / li >
< li class = "chapter " data-level = "5.4" data-path = "../http/default_interceptors.html" >
< a href = "../http/default_interceptors.html" >
Default Interceptors
< / a >
< / li >
< li class = "chapter " data-level = "5.5" data-path = "../http/transforming_interceptor_chain.html" >
< a href = "../http/transforming_interceptor_chain.html" >
Transforming Interceptor Chain
< / a >
< / li >
< li class = "header" > Frontend< / li >
< li class = "chapter " data-level = "6.1" data-path = "../frontend/basics.html" >
< a href = "../frontend/basics.html" >
Basics
< / a >
< / li >
< li class = "chapter " data-level = "6.2" data-path = "../frontend/browser.html" >
< a href = "../frontend/browser.html" >
Browser integration
< / a >
< / li >
< li class = "chapter " data-level = "6.3" data-path = "../frontend/controllers.html" >
< a href = "../frontend/controllers.html" >
Controllers
< / a >
< / li >
< li class = "header" > Advanced< / li >
< li class = "chapter " data-level = "7.1" data-path = "../advanced/configuring_routers.html" >
< a href = "../advanced/configuring_routers.html" >
Configuring Routers
< / a >
< / li >
< li class = "chapter " data-level = "7.2" data-path = "../advanced/composing_routers.html" >
< a href = "../advanced/composing_routers.html" >
Composing Routers
< / a >
< / li >
< li class = "chapter " data-level = "7.3" data-path = "../advanced/different_routers.html" >
< a href = "../advanced/different_routers.html" >
Different Routers
< / a >
< / li >
< li class = "chapter " data-level = "7.4" data-path = "../advanced/route_validation.html" >
< a href = "../advanced/route_validation.html" >
Route Validation
< / a >
< / li >
< li class = "chapter " data-level = "7.5" data-path = "../advanced/dev_workflow.html" >
< a href = "../advanced/dev_workflow.html" >
Dev Workflow
< / a >
< / li >
< li class = "chapter " data-level = "7.6" data-path = "../advanced/shared_routes.html" >
< a href = "../advanced/shared_routes.html" >
Shared Routes
< / a >
< / li >
< li class = "header" > Misc< / li >
< li class = "chapter " data-level = "8.1" data-path = "../performance.html" >
< a href = "../performance.html" >
Performance
< / a >
< / li >
< li class = "chapter " data-level = "8.2" data-path = "../development.html" >
< a href = "../development.html" >
Development Instructions
< / a >
< / li >
< li class = "chapter " data-level = "8.3" data-path = "../faq.html" >
< a href = "../faq.html" >
FAQ
< / a >
< / li >
< li class = "divider" > < / li >
< li >
< a href = "https://www.gitbook.com" target = "blank" class = "gitbook-link" >
Published with GitBook
< / a >
< / li >
< / ul >
< / nav >
< / div >
< div class = "book-body" >
< div class = "body-inner" >
< div class = "book-header" role = "navigation" >
<!-- Title -->
< h1 >
< i class = "fa fa-circle-o-notch fa-spin" > < / i >
< a href = ".." > Exception Handling with Ring< / a >
< / h1 >
< / div >
< div class = "page-wrapper" tabindex = "-1" role = "main" >
< div class = "page-inner" >
< div id = "book-search-results" >
< div class = "search-noresults" >
< section class = "normal markdown-section" >
< h1 id = "exception-handling-with-ring" > Exception Handling with Ring< / h1 >
< pre > < code class = "lang-clj" > [metosin/reitit-middleware < span class = "hljs-string" > " 0.4.2" < / span > ]
< / code > < / pre >
< p > Exceptions thrown in router creation can be < a href = "../basics/error_messages.html" > handled with custom exception handler< / a > . By default, exceptions thrown at runtime from a handler or a middleware are not caught by the < code > reitit.ring/ring-handler< / code > . A good practise is a have an top-level exception handler to log and format the errors for clients.< / p >
< pre > < code class = "lang-clj" > (< span class = "hljs-name" > require< / span > ' [reitit.ring.middleware.exception < span class = "hljs-symbol" > :as< / span > exception])
< / code > < / pre >
< h3 id = "exceptionexception-middleware" > < code > exception/exception-middleware< / code > < / h3 >
< p > A preconfigured middleware using < code > exception/default-handlers< / code > . Catches:< / p >
< ul >
< li > Request & response < a href = "coercion.html" > Coercion< / a > exceptions< / li >
< li > < a href = "https://github.com/metosin/muuntaja" target = "_blank" > Muuntaja< / a > decode exceptions< / li >
< li > Exceptions with < code > :type< / code > of < code > :reitit.ring/response< / code > , returning < code > :response< / code > key from < code > ex-data< / code > .< / li >
< li > Safely all other exceptions< / li >
< / ul >
< pre > < code class = "lang-clj" > (< span class = "hljs-name" > require< / span > ' [reitit.ring < span class = "hljs-symbol" > :as< / span > ring])
(< span class = "hljs-name" > < span class = "hljs-builtin-name" > def< / span > < / span > app
(< span class = "hljs-name" > ring/ring-handler< / span >
(< span class = "hljs-name" > ring/router< / span >
[< span class = "hljs-string" > " /fail" < / span > (< span class = "hljs-name" > < span class = "hljs-builtin-name" > fn< / span > < / span > [_] (< span class = "hljs-name" > < span class = "hljs-builtin-name" > throw< / span > < / span > (< span class = "hljs-name" > Exception.< / span > < span class = "hljs-string" > " fail" < / span > )))]
{< span class = "hljs-symbol" > :data< / span > {< span class = "hljs-symbol" > :middleware< / span > [exception/exception-middleware]}})))
(< span class = "hljs-name" > app< / span > {< span class = "hljs-symbol" > :request-method< / span > < span class = "hljs-symbol" > :get< / span > , < span class = "hljs-symbol" > :uri< / span > < span class = "hljs-string" > " /fail" < / span > })
< span class = "hljs-comment" > ;{:status 500< / span >
< span class = "hljs-comment" > ; :body {:type " exception" < / span >
< span class = "hljs-comment" > ; :class " java.lang.Exception" }}< / span >
< / code > < / pre >
< h3 id = "exceptioncreate-exception-middleware" > < code > exception/create-exception-middleware< / code > < / h3 >
< p > Creates the exception-middleware with custom options. Takes a map of < code > identifier => exception request => response< / code > that is used to select the exception handler for the thrown/raised exception identifier. Exception identifier is either a < code > Keyword< / code > or a Exception Class.< / p >
< p > The following handlers are available by default:< / p >
< table >
< thead >
< tr >
< th > key< / th >
< th > description< / th >
< / tr >
< / thead >
< tbody >
< tr >
< td > < code > :reitit.ring/response< / code > < / td >
< td > value in ex-data key < code > :response< / code > will be returned< / td >
< / tr >
< tr >
< td > < code > :muuntaja/decode< / code > < / td >
< td > handle Muuntaja decoding exceptions< / td >
< / tr >
< tr >
< td > < code > :reitit.coercion/request-coercion< / code > < / td >
< td > request coercion errors (http 400 response)< / td >
< / tr >
< tr >
< td > < code > :reitit.coercion/response-coercion< / code > < / td >
< td > response coercion errors (http 500 response)< / td >
< / tr >
< tr >
< td > < code > ::exception/default< / code > < / td >
< td > a default exception handler if nothing else matched (default < code > exception/default-handler< / code > ).< / td >
< / tr >
< tr >
< td > < code > ::exception/wrap< / code > < / td >
< td > a 3-arity handler to wrap the actual handler < code > handler exception request => response< / code > (no default).< / td >
< / tr >
< / tbody >
< / table >
< p > The handler is selected from the options map by exception identifier in the following lookup order:< / p >
< p > 1) < code > :type< / code > of exception ex-data
2) Class of exception
3) < code > :type< / code > ancestors of exception ex-data
4) Super Classes of exception
5) The ::default handler< / p >
< pre > < code class = "lang-clj" > < span class = "hljs-comment" > ;; type hierarchy< / span >
(< span class = "hljs-name" > derive< / span > < span class = "hljs-symbol" > ::error< / span > < span class = "hljs-symbol" > ::exception< / span > )
(< span class = "hljs-name" > derive< / span > < span class = "hljs-symbol" > ::failure< / span > < span class = "hljs-symbol" > ::exception< / span > )
(< span class = "hljs-name" > derive< / span > < span class = "hljs-symbol" > ::horror< / span > < span class = "hljs-symbol" > ::exception< / span > )
(< span class = "hljs-name" > < span class = "hljs-builtin-name" > defn< / span > < / span > handler [message exception request]
{< span class = "hljs-symbol" > :status< / span > < span class = "hljs-number" > 500< / span >
< span class = "hljs-symbol" > :body< / span > {< span class = "hljs-symbol" > :message< / span > message
< span class = "hljs-symbol" > :exception< / span > (< span class = "hljs-name" > .getClass< / span > exception)
< span class = "hljs-symbol" > :data< / span > (< span class = "hljs-name" > ex-data< / span > exception)
< span class = "hljs-symbol" > :uri< / span > (< span class = "hljs-symbol" > :uri< / span > request)}})
(< span class = "hljs-name" > < span class = "hljs-builtin-name" > def< / span > < / span > exception-middleware
(< span class = "hljs-name" > exception/create-exception-middleware< / span >
(< span class = "hljs-name" > < span class = "hljs-builtin-name" > merge< / span > < / span >
exception/default-handlers
{< span class = "hljs-comment" > ;; ex-data with :type ::error< / span >
< span class = "hljs-symbol" > ::error< / span > (< span class = "hljs-name" > < span class = "hljs-builtin-name" > partial< / span > < / span > handler < span class = "hljs-string" > " error" < / span > )
< span class = "hljs-comment" > ;; ex-data with ::exception or ::failure< / span >
< span class = "hljs-symbol" > ::exception< / span > (< span class = "hljs-name" > < span class = "hljs-builtin-name" > partial< / span > < / span > handler < span class = "hljs-string" > " exception" < / span > )
< span class = "hljs-comment" > ;; SQLException and all it' s child classes< / span >
java.sql.SQLException (< span class = "hljs-name" > < span class = "hljs-builtin-name" > partial< / span > < / span > handler < span class = "hljs-string" > " sql-exception" < / span > )
< span class = "hljs-comment" > ;; override the default handler< / span >
< span class = "hljs-symbol" > ::exception/default< / span > (< span class = "hljs-name" > < span class = "hljs-builtin-name" > partial< / span > < / span > handler < span class = "hljs-string" > " default" < / span > )
< span class = "hljs-comment" > ;; print stack-traces for all exceptions< / span >
< span class = "hljs-symbol" > ::exception/wrap< / span > (< span class = "hljs-name" > < span class = "hljs-builtin-name" > fn< / span > < / span > [handler e request]
(< span class = "hljs-name" > println< / span > < span class = "hljs-string" > " ERROR" < / span > (< span class = "hljs-name" > pr-str< / span > (< span class = "hljs-symbol" > :uri< / span > request)))
(< span class = "hljs-name" > handler< / span > e request))})))
(< span class = "hljs-name" > < span class = "hljs-builtin-name" > def< / span > < / span > app
(< span class = "hljs-name" > ring/ring-handler< / span >
(< span class = "hljs-name" > ring/router< / span >
[< span class = "hljs-string" > " /fail" < / span > (< span class = "hljs-name" > < span class = "hljs-builtin-name" > fn< / span > < / span > [_] (< span class = "hljs-name" > < span class = "hljs-builtin-name" > throw< / span > < / span > (< span class = "hljs-name" > ex-info< / span > < span class = "hljs-string" > " fail" < / span > {< span class = "hljs-symbol" > :type< / span > < span class = "hljs-symbol" > ::failue< / span > })))]
{< span class = "hljs-symbol" > :data< / span > {< span class = "hljs-symbol" > :middleware< / span > [exception-middleware]}})))
(< span class = "hljs-name" > app< / span > {< span class = "hljs-symbol" > :request-method< / span > < span class = "hljs-symbol" > :get< / span > , < span class = "hljs-symbol" > :uri< / span > < span class = "hljs-string" > " /fail" < / span > })
< span class = "hljs-comment" > ; ERROR " /fail" < / span >
< span class = "hljs-comment" > ; => {:status 500,< / span >
< span class = "hljs-comment" > ; :body {:message " default" < / span >
< span class = "hljs-comment" > ; :exception clojure.lang.ExceptionInfo< / span >
< span class = "hljs-comment" > ; :data {:type :user/failue}< / span >
< span class = "hljs-comment" > ; :uri " /fail" }}< / span >
< / code > < / pre >
< / section >
< / div >
< div class = "search-results" >
< div class = "has-results" >
< h1 class = "search-results-title" > < span class = 'search-results-count' > < / span > results matching "< span class = 'search-query' > < / span > "< / h1 >
< ul class = "search-results-list" > < / ul >
< / div >
< div class = "no-results" >
< h1 class = "search-results-title" > No results matching "< span class = 'search-query' > < / span > "< / h1 >
< / div >
< / div >
< / div >
< / div >
< / div >
< / div >
< a href = "middleware_registry.html" class = "navigation navigation-prev " aria-label = "Previous page: Middleware Registry" >
< i class = "fa fa-angle-left" > < / i >
< / a >
< a href = "default_middleware.html" class = "navigation navigation-next " aria-label = "Next page: Default Middleware" >
< i class = "fa fa-angle-right" > < / i >
< / a >
< / div >
< script >
var gitbook = gitbook || [];
gitbook.push(function() {
2020-05-12 16:45:10 +00:00
gitbook.page.hasChanged({"page":{"title":"Exception Handling with Ring","level":"4.10","depth":1,"next":{"title":"Default Middleware","level":"4.11","depth":1,"path":"ring/default_middleware.md","ref":"ring/default_middleware.md","articles":[]},"previous":{"title":"Middleware Registry","level":"4.9","depth":1,"path":"ring/middleware_registry.md","ref":"ring/middleware_registry.md","articles":[]},"dir":"ltr"},"config":{"plugins":["hints","editlink","github","highlight"],"root":"doc","styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"github":{"url":"https://github.com/metosin/reitit"},"editlink":{"label":"Edit This Page","multilingual":false,"base":"https://github.com/metosin/reitit/tree/master/doc"},"search":{},"hints":{"danger":"fa fa-exclamation-circle","info":"fa fa-info-circle","tip":"fa fa-mortar-board","working":"fa fa-wrench"},"lunr":{"maxIndexSize":1000000,"ignoreSpecialCharacters":false},"fontsettings":{"theme":"white","family":"sans","size":2},"highlight":{},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false}},"theme":"default","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"README.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"gitbook":"*"},"file":{"path":"ring/exceptions.md","mtime":"2020-05-12T16:44:03.515Z","type":"markdown"},"gitbook":{"version":"3.2.3","time":"2020-05-12T16:45:06.213Z"},"basePath":"..","book":{"language":""}});
2020-03-10 15:01:52 +00:00
});
< / script >
< / div >
< script src = "../gitbook/gitbook.js" > < / script >
< script src = "../gitbook/theme.js" > < / script >
< script src = "../gitbook/gitbook-plugin-editlink/plugin.js" > < / script >
< script src = "../gitbook/gitbook-plugin-github/plugin.js" > < / script >
< script src = "../gitbook/gitbook-plugin-search/search-engine.js" > < / script >
< script src = "../gitbook/gitbook-plugin-search/search.js" > < / script >
< script src = "../gitbook/gitbook-plugin-lunr/lunr.min.js" > < / script >
< script src = "../gitbook/gitbook-plugin-lunr/search-lunr.js" > < / script >
< script src = "../gitbook/gitbook-plugin-sharing/buttons.js" > < / script >
< script src = "../gitbook/gitbook-plugin-fontsettings/fontsettings.js" > < / script >
< / body >
< / html >
