From a3448adee28b954f6c20f87df500f5d32cc95761 Mon Sep 17 00:00:00 2001
From: guqing <38999863+guqing@users.noreply.github.com>
Date: Tue, 18 Oct 2022 10:22:09 +0800
Subject: [PATCH] feat: add favicon head processor (#2582)
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#### What type of PR is this?
/kind feature
/area core
/milestone 2.0

#### What this PR does / why we need it:
模板渲染自动填充 Favicon 到 head 标签
#### Which issue(s) this PR fixes:

Fixes #2581

#### Special notes for your reviewer:
how to test it?
在 console 系统设置 -> 基础设置 填写 Favicon 后，到主题端能到看它

/cc @halo-dev/sig-halo
#### Does this PR introduce a user-facing change?

```release-note
支持设置 Favicon
```
---
 .../dialect/DefaultFaviconHeadProcessor.java  | 46 +++++++++++++++++++
 .../dialect/HaloProcessorDialectTest.java     | 12 +++++
 2 files changed, 58 insertions(+)
 create mode 100644 src/main/java/run/halo/app/theme/dialect/DefaultFaviconHeadProcessor.java

diff --git a/src/main/java/run/halo/app/theme/dialect/DefaultFaviconHeadProcessor.java b/src/main/java/run/halo/app/theme/dialect/DefaultFaviconHeadProcessor.java
new file mode 100644
index 000000000..d8986ea64
--- /dev/null
+++ b/src/main/java/run/halo/app/theme/dialect/DefaultFaviconHeadProcessor.java
@@ -0,0 +1,46 @@
+package run.halo.app.theme.dialect;
+
+import lombok.AllArgsConstructor;
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.stereotype.Component;
+import org.thymeleaf.context.ITemplateContext;
+import org.thymeleaf.model.IModel;
+import org.thymeleaf.model.IModelFactory;
+import org.thymeleaf.processor.element.IElementModelStructureHandler;
+import reactor.core.publisher.Mono;
+import run.halo.app.infra.SystemConfigurableEnvironmentFetcher;
+import run.halo.app.infra.SystemSetting;
+
+/**
+ * Theme template <code>head</code> tag snippet injection processor for favicon.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+@Component
+@AllArgsConstructor
+public class DefaultFaviconHeadProcessor implements TemplateHeadProcessor {
+
+    private final SystemConfigurableEnvironmentFetcher fetcher;
+
+    @Override
+    public Mono<Void> process(ITemplateContext context, IModel model,
+        IElementModelStructureHandler structureHandler) {
+        return fetchBasicSetting()
+            .filter(basic -> StringUtils.isNotBlank(basic.getFavicon()))
+            .map(basic -> {
+                IModelFactory modelFactory = context.getModelFactory();
+                model.add(modelFactory.createText(faviconSnippet(basic.getFavicon())));
+                return model;
+            })
+            .then();
+    }
+
+    private String faviconSnippet(String favicon) {
+        return String.format("<link rel=\"icon\" href=\"%s\" />\n", favicon);
+    }
+
+    private Mono<SystemSetting.Basic> fetchBasicSetting() {
+        return fetcher.fetch(SystemSetting.Basic.GROUP, SystemSetting.Basic.class);
+    }
+}
diff --git a/src/test/java/run/halo/app/theme/dialect/HaloProcessorDialectTest.java b/src/test/java/run/halo/app/theme/dialect/HaloProcessorDialectTest.java
index ee5960739..74c219dfc 100644
--- a/src/test/java/run/halo/app/theme/dialect/HaloProcessorDialectTest.java
+++ b/src/test/java/run/halo/app/theme/dialect/HaloProcessorDialectTest.java
@@ -69,6 +69,7 @@ class HaloProcessorDialectTest {
         Map<String, TemplateHeadProcessor> map = new HashMap<>();
         map.put("postTemplateHeadProcessor", new PostTemplateHeadProcessor(postFinder));
         map.put("templateGlobalHeadProcessor", new TemplateGlobalHeadProcessor(fetcher));
+        map.put("faviconHeadProcessor", new DefaultFaviconHeadProcessor(fetcher));
         lenient().when(applicationContext.getBeansOfType(TemplateHeadProcessor.class))
             .thenReturn(map);
 
@@ -85,6 +86,11 @@ class HaloProcessorDialectTest {
 
     @Test
     void globalHeadAndFooterProcessors() {
+        SystemSetting.Basic basic = new SystemSetting.Basic();
+        basic.setFavicon("favicon.ico");
+        when(fetcher.fetch(eq(SystemSetting.Basic.GROUP),
+            eq(SystemSetting.Basic.class))).thenReturn(Mono.just(basic));
+
         Context context = getContext();
 
         String result = templateEngine.process("index", context);
@@ -95,6 +101,7 @@ class HaloProcessorDialectTest {
                 <meta charset="UTF-8" />
                 <title>Index</title>
               <meta name="global-head-test" content="test" />
+            <link rel="icon" href="favicon.ico" />
             </head>
               <body>
                 <p>index</p>
@@ -124,6 +131,11 @@ class HaloProcessorDialectTest {
             .metadata(metadata).build();
         when(postFinder.getByName(eq("fake-post"))).thenReturn(postVo);
 
+        SystemSetting.Basic basic = new SystemSetting.Basic();
+        basic.setFavicon(null);
+        when(fetcher.fetch(eq(SystemSetting.Basic.GROUP),
+            eq(SystemSetting.Basic.class))).thenReturn(Mono.just(basic));
+
         String result = templateEngine.process("post", context);
         assertThat(result).isEqualTo("""
             <!DOCTYPE html>