Prepend context path to context relative URLs in htmx response headers

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HtmxHandlerInterceptor.java

@@ -10,7 +10,6 @@
 import org.springframework.web.servlet.HandlerInterceptor;
 import org.springframework.web.servlet.ModelAndView;
 import org.springframework.web.servlet.View;
-import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 
 import java.lang.reflect.Method;
 import java.time.Duration;
@@ -45,7 +44,7 @@ private void buildAndRender(HtmxResponse htmxResponse, ModelAndView mav, HttpSer
         View v = htmxResponseHandlerMethodReturnValueHandler.toView(htmxResponse);
         try {
             v.render(mav.getModel(), request, response);
-            htmxResponseHandlerMethodReturnValueHandler.addHxHeaders(htmxResponse, response);
+            htmxResponseHandlerMethodReturnValueHandler.addHxHeaders(htmxResponse, request, response);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }
@@ -58,9 +57,9 @@ public boolean preHandle(HttpServletRequest request,
 
         if (handler instanceof HandlerMethod) {
             Method method = ((HandlerMethod) handler).getMethod();
-            setHxLocation(response, method);
+            setHxLocation(request, response, method);
             setHxPushUrl(request, response, method);
-            setHxRedirect(response, method);
+            setHxRedirect(request, response, method);
             setHxReplaceUrl(request, response, method);
             setHxReswap(response, method);
             setHxRetarget(response, method);
@@ -81,14 +80,15 @@ private void setVary(HttpServletRequest request, HttpServletResponse response) {
         }
     }
 
-    private void setHxLocation(HttpServletResponse response, Method method) {
+    private void setHxLocation(HttpServletRequest request, HttpServletResponse response, Method method) {
         HxLocation methodAnnotation = AnnotatedElementUtils.findMergedAnnotation(method, HxLocation.class);
         if (methodAnnotation != null) {
             var location = convertToLocation(methodAnnotation);
             if (location.hasContextData()) {
+                location.setPath(UrlUtils.createTargetUrl(request, location.getPath(), methodAnnotation.contextRelative()));
                 setHeaderJsonValue(response, HtmxResponseHeader.HX_LOCATION, location);
             } else {
-                setHeader(response, HtmxResponseHeader.HX_LOCATION, location.getPath());
+                setHeader(response, HtmxResponseHeader.HX_LOCATION, UrlUtils.createTargetUrl(request, location.getPath(), methodAnnotation.contextRelative()));
             }
         }
     }
@@ -99,15 +99,15 @@ private void setHxPushUrl(HttpServletRequest request, HttpServletResponse respon
             if (HtmxValue.TRUE.equals(methodAnnotation.value())) {
                 setHeader(response, HX_PUSH_URL, getRequestUrl(request));
             } else {
-                setHeader(response, HX_PUSH_URL, methodAnnotation.value());
+                setHeader(response, HX_PUSH_URL, UrlUtils.createTargetUrl(request, methodAnnotation.value(), methodAnnotation.contextRelative()));
             }
         }
     }
 
-    private void setHxRedirect(HttpServletResponse response, Method method) {
+    private void setHxRedirect(HttpServletRequest request, HttpServletResponse response, Method method) {
         HxRedirect methodAnnotation = AnnotatedElementUtils.findMergedAnnotation(method, HxRedirect.class);
         if (methodAnnotation != null) {
-            setHeader(response, HX_REDIRECT, methodAnnotation.value());
+            setHeader(response, HX_REDIRECT, UrlUtils.createTargetUrl(request, methodAnnotation.value(), methodAnnotation.contextRelative()));
         }
     }
 
@@ -117,7 +117,7 @@ private void setHxReplaceUrl(HttpServletRequest request, HttpServletResponse res
             if (HtmxValue.TRUE.equals(methodAnnotation.value())) {
                 setHeader(response, HX_REPLACE_URL, getRequestUrl(request));
             } else {
-                setHeader(response, HX_REPLACE_URL, methodAnnotation.value());
+                setHeader(response, HX_REPLACE_URL, UrlUtils.createTargetUrl(request, methodAnnotation.value(), methodAnnotation.contextRelative()));
             }
         }
     }

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HtmxResponse.java

@@ -1,13 +1,13 @@
 package io.github.wimdeblauwe.htmx.spring.boot.mvc;
 
-import java.util.*;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.util.Assert;
 import org.springframework.web.servlet.ModelAndView;
 import org.springframework.web.servlet.View;
 
+import java.util.*;
+
 /**
  * Used as a controller method return type to specify htmx-related response headers
  * and returning multiple template partials in a single response.
@@ -27,6 +27,7 @@ public final class HtmxResponse {
     private final Set<HtmxTrigger> triggersAfterSwap;
     private final String replaceUrl;
     private final String reselect;
+    private final boolean contextRelative;
     // TODO should also be final after switching to builder pattern
     private String retarget;
     private boolean refresh;
@@ -55,11 +56,12 @@ public HtmxResponse() {
         this.triggersAfterSwap = new LinkedHashSet<>();
         this.replaceUrl = null;
         this.reselect = null;
+        this.contextRelative = true;
     }
 
     HtmxResponse(Set<ModelAndView> views, Set<HtmxTrigger> triggers, Set<HtmxTrigger> triggersAfterSettle,
                  Set<HtmxTrigger> triggersAfterSwap, String retarget, boolean refresh, String redirect,
-                 String pushUrl, String replaceUrl, String reselect, HtmxReswap reswap, HtmxLocation location) {
+                 String pushUrl, String replaceUrl, String reselect, HtmxReswap reswap, HtmxLocation location, boolean contextRelative) {
         this.views = views;
         this.triggers = triggers;
         this.triggersAfterSettle = triggersAfterSettle;
@@ -72,6 +74,7 @@ public HtmxResponse() {
         this.reselect = reselect;
         this.reswap = reswap;
         this.location = location;
+        this.contextRelative = contextRelative;
     }
 
     /**
@@ -380,6 +383,10 @@ public boolean isRefresh() {
         return refresh;
     }
 
+    public boolean isContextRelative() {
+        return contextRelative;
+    }
+
     /**
      * @deprecated will be removed in 4.0.
      */
@@ -406,6 +413,7 @@ public static final class Builder {
         private HtmxReswap reswap;
         private String retarget;
         private String reselect;
+        private boolean contextRelative = true;
 
         /**
          * Merges another {@link HtmxResponse} into this builder.
@@ -468,7 +476,22 @@ public HtmxResponse build() {
                     replaceUrl,
                     reselect,
                     reswap,
-                    location);
+                    location,
+                    contextRelative);
+        }
+
+        /**
+         * Set whether URLs used in the htmx response that starts with a slash ("/") should be interpreted as
+         * relative to the current ServletContext, i.e. as relative to the web application root.
+         * Default is "true": A URL that starts with a slash will be interpreted as relative to
+         * the web application root, i.e. the context path will be prepended to the URL.
+         *
+         * @param contextRelative whether to interpret URLs in the htmx response as relative to the current ServletContext
+         * @return the builder
+         */
+        public Builder contextRelative(boolean contextRelative) {
+            this.contextRelative = contextRelative;
+            return this;
         }
 
         /**
@@ -728,8 +751,8 @@ private static void mergeTriggers(Collection<HtmxTrigger> triggers, Collection<H
             for (HtmxTrigger otherTrigger : otherTriggers) {
                 if (LOGGER.isWarnEnabled()) {
                     Optional<HtmxTrigger> otrigger = triggers.stream()
-                        .filter(t -> t.getEventName().equals(otherTrigger.getEventName()))
-                        .findFirst();
+                                                             .filter(t -> t.getEventName().equals(otherTrigger.getEventName()))
+                                                             .findFirst();
 
                     if (otrigger.isPresent()) {
                         LOGGER.warn("Duplicate trigger event '{}' found. Details '{}' will be overwritten by with '{}'", otherTrigger.getEventName(), otrigger.get().getEventDetail(), otherTrigger.getEventDetail());

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HtmxResponseHandlerMethodReturnValueHandler.java

@@ -2,6 +2,7 @@
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.core.MethodParameter;
@@ -47,7 +48,10 @@ public void handleReturnValue(Object returnValue,
         HtmxResponse htmxResponse = (HtmxResponse) returnValue;
         mavContainer.setView(toView(htmxResponse));
 
-        addHxHeaders(htmxResponse, webRequest.getNativeResponse(HttpServletResponse.class));
+        HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
+        HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class);
+
+        addHxHeaders(htmxResponse, request, response);
     }
 
     View toView(HtmxResponse htmxResponse) {
@@ -74,26 +78,28 @@ View toView(HtmxResponse htmxResponse) {
         };
     }
 
-    void addHxHeaders(HtmxResponse htmxResponse, HttpServletResponse response) {
+    void addHxHeaders(HtmxResponse htmxResponse, HttpServletRequest request, HttpServletResponse response) {
         addHxTriggerHeaders(response, HtmxResponseHeader.HX_TRIGGER, htmxResponse.getTriggersInternal());
         addHxTriggerHeaders(response, HtmxResponseHeader.HX_TRIGGER_AFTER_SETTLE, htmxResponse.getTriggersAfterSettleInternal());
         addHxTriggerHeaders(response, HtmxResponseHeader.HX_TRIGGER_AFTER_SWAP, htmxResponse.getTriggersAfterSwapInternal());
 
         if (htmxResponse.getLocation() != null) {
-            if (htmxResponse.getLocation().hasContextData()) {
-                setHeaderJsonValue(response, HtmxResponseHeader.HX_LOCATION.getValue(), htmxResponse.getLocation());
+            HtmxLocation location = htmxResponse.getLocation();
+            if (location.hasContextData()) {
+                location.setPath(UrlUtils.createTargetUrl(request, location.getPath(), htmxResponse.isContextRelative()));
+                setHeaderJsonValue(response, HtmxResponseHeader.HX_LOCATION.getValue(), location);
             } else {
-                response.setHeader(HtmxResponseHeader.HX_LOCATION.getValue(), htmxResponse.getLocation().getPath());
+                response.setHeader(HtmxResponseHeader.HX_LOCATION.getValue(), UrlUtils.createTargetUrl(request, location.getPath(), htmxResponse.isContextRelative()));
             }
         }
         if (htmxResponse.getReplaceUrl() != null) {
-            response.setHeader(HtmxResponseHeader.HX_REPLACE_URL.getValue(), htmxResponse.getReplaceUrl());
+            response.setHeader(HtmxResponseHeader.HX_REPLACE_URL.getValue(), UrlUtils.createTargetUrl(request, htmxResponse.getReplaceUrl(), htmxResponse.isContextRelative()));
         }
         if (htmxResponse.getPushUrl() != null) {
-            response.setHeader(HtmxResponseHeader.HX_PUSH_URL.getValue(), htmxResponse.getPushUrl());
+            response.setHeader(HtmxResponseHeader.HX_PUSH_URL.getValue(), UrlUtils.createTargetUrl(request, htmxResponse.getPushUrl(), htmxResponse.isContextRelative()));
         }
         if (htmxResponse.getRedirect() != null) {
-            response.setHeader(HtmxResponseHeader.HX_REDIRECT.getValue(), htmxResponse.getRedirect());
+            response.setHeader(HtmxResponseHeader.HX_REDIRECT.getValue(), UrlUtils.createTargetUrl(request, htmxResponse.getRedirect(), htmxResponse.isContextRelative()));
         }
         if (htmxResponse.isRefresh()) {
             response.setHeader(HtmxResponseHeader.HX_REFRESH.getValue(), "true");

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HxLocation.java

@@ -51,5 +51,9 @@
      * How the response will be swapped in relative to the target
      */
     String swap() default "";
+    /**
+     * If the path should be interpreted as context relative if it starts with a slash ("/").
+     */
+    boolean contextRelative() default true;
 
 }

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HxPushUrl.java

@@ -27,5 +27,9 @@
      * The value for the {@code HX-Push-Url} response header.
      */
     String value() default HtmxValue.TRUE;
+    /**
+     * If the URL should be interpreted as context relative if it starts with a slash ("/").
+     */
+    boolean contextRelative() default true;
 
 }

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HxRedirect.java

@@ -18,5 +18,9 @@
      * The URL to use to do a client-side redirect to a new location.
      */
     String value();
+    /**
+     * If the URL should be interpreted as context relative if it starts with a slash ("/").
+     */
+    boolean contextRelative() default true;
 
 }

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HxReplaceUrl.java

@@ -28,5 +28,9 @@
      * The value for the {@code HX-Replace-Url} response header.
      */
     String value() default HtmxValue.TRUE;
+    /**
+     * If the URL should be interpreted as context relative if it starts with a slash ("/").
+     */
+    boolean contextRelative() default true;
 
 }

htmx-spring-boot/src/main/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/UrlUtils.java

@@ -0,0 +1,35 @@
+package io.github.wimdeblauwe.htmx.spring.boot.mvc;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+class UrlUtils {
+
+    /**
+     * Creates a target URL by prepending the context path if {@code contextRelative}
+     * is {@code true} and the URL starts with a slash ("/").
+     *
+     * @param request
+     * @param url
+     * @param contextRelative
+     * @return
+     */
+    static String createTargetUrl(HttpServletRequest request, String url, boolean contextRelative) {
+        if (contextRelative && url.startsWith("/")) {
+            // Do not apply context path to relative URLs.
+            return getContextPath(request) + url;
+        }
+        return url;
+    }
+
+    static String getContextPath(HttpServletRequest request) {
+        String contextPath = request.getContextPath();
+        while (contextPath.startsWith("//")) {
+            contextPath = contextPath.substring(1);
+        }
+        return contextPath;
+    }
+
+    private UrlUtils() {
+    }
+
+}

htmx-spring-boot/src/test/java/io/github/wimdeblauwe/htmx/spring/boot/mvc/HtmxHandlerInterceptorTest.java

@@ -128,62 +128,62 @@ public void testHxRefresh() throws Exception {
 
     @Test
     public void testHxLocationWithContextData() throws Exception {
-        mockMvc.perform(get("/hx-location-with-context-data"))
+        mockMvc.perform(get("/test/hx-location-with-context-data").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Location", "{\"path\":\"/path\",\"source\":\"source\",\"event\":\"event\",\"handler\":\"handler\",\"target\":\"target\",\"swap\":\"swap\"}"));
+               .andExpect(header().string("HX-Location", "{\"path\":\"/test/path\",\"source\":\"source\",\"event\":\"event\",\"handler\":\"handler\",\"target\":\"target\",\"swap\":\"swap\"}"));
     }
 
     @Test
     public void testHxLocationWithoutContextData() throws Exception {
-        mockMvc.perform(get("/hx-location-without-context-data"))
+        mockMvc.perform(get("/test/hx-location-without-context-data").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Location", "/path"));
+               .andExpect(header().string("HX-Location", "/test/path"));
     }
 
     @Test
     public void testHxPushUrlPath() throws Exception {
-        mockMvc.perform(get("/hx-push-url-path"))
+        mockMvc.perform(get("/test/hx-push-url-path").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Push-Url", "/path"));
+               .andExpect(header().string("HX-Push-Url", "/test/path"));
     }
     @Test
     public void testHxPushUrl() throws Exception {
-        mockMvc.perform(get("/hx-push-url?test=hello"))
+        mockMvc.perform(get("/test/hx-push-url?test=hello").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Push-Url", "/hx-push-url?test=hello"));
+               .andExpect(header().string("HX-Push-Url", "/test/hx-push-url?test=hello"));
     }
 
     @Test
     public void testHxPushUrlFalse() throws Exception {
-        mockMvc.perform(get("/hx-push-url-false?test=hello"))
+        mockMvc.perform(get("/test/hx-push-url-false?test=hello").contextPath("/test"))
                .andExpect(status().isOk())
                .andExpect(header().string("HX-Push-Url", "false"));
     }
 
     @Test
     public void testHxRedirect() throws Exception {
-        mockMvc.perform(get("/hx-redirect"))
+        mockMvc.perform(get("/test/hx-redirect").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Redirect", "/path"));
+               .andExpect(header().string("HX-Redirect", "/test/path"));
     }
 
     @Test
     public void testHxReplaceUrlPath() throws Exception {
-        mockMvc.perform(get("/hx-replace-url-path"))
+        mockMvc.perform(get("/test/hx-replace-url-path").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Replace-Url", "/path"));
+               .andExpect(header().string("HX-Replace-Url", "/test/path"));
     }
 
     @Test
     public void testHxReplaceUrl() throws Exception {
-        mockMvc.perform(get("/hx-replace-url?test=hello&test2=hello2"))
+        mockMvc.perform(get("/test/hx-replace-url?test=hello&test2=hello2").contextPath("/test"))
                .andExpect(status().isOk())
-               .andExpect(header().string("HX-Replace-Url", "/hx-replace-url?test=hello&test2=hello2"));
+               .andExpect(header().string("HX-Replace-Url", "/test/hx-replace-url?test=hello&test2=hello2"));
     }
 
     @Test
     public void testHxReplaceUrlFalse() throws Exception {
-        mockMvc.perform(get("/hx-replace-url-false?test=hello"))
+        mockMvc.perform(get("/test/hx-replace-url-false?test=hello").contextPath("/test"))
                .andExpect(status().isOk())
                .andExpect(header().string("HX-Replace-Url", "false"));
     }