feat(openresty): render origin error page directives

Wire origin error page into OpenResty proxy route rendering: ConfigSnapshot fields, default HTML template SupportFile, proxy_intercept_errors + error_page with status-preserving internal Lua location, and Agent placeholder substitution for __OPENFLARE_ERROR_PAGE_TMPL__. Pages routes are excluded.
2026-10-05 07:26:36 +08:00 · 2026-08-06 13:52:40 +08:00
parent 07e835c543
commit 68d8f786cc
6 changed files with 418 additions and 44 deletions
@@ -0,0 +1,172 @@
+package openresty
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const (
+	// OriginErrorPageSupportPath is the SupportFile path for the origin error HTML template.
+	OriginErrorPageSupportPath = "error_pages/origin_error.html.tmpl"
+
+	// OriginErrorPageInternalLocation is the internal nginx location that serves the error body.
+	OriginErrorPageInternalLocation = "/__openflare_origin_error"
+
+	defaultOriginErrorPageStatusTag = "500-599"
+)
+
+// DefaultOriginErrorPageHTML is the built-in Cloudflare-style origin error page.
+// Placeholders {{status}} and {{host}} are substituted at request time by Lua.
+const DefaultOriginErrorPageHTML = `<!DOCTYPE html>
+<html lang="zh-CN">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>{{status}} | 源站暂时无法提供服务</title>
+<style>
+  :root { color-scheme: light dark; }
+  * { box-sizing: border-box; }
+  body {
+    margin: 0;
+    min-height: 100vh;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
+    background: #f6f7f9;
+    color: #1f2937;
+  }
+  @media (prefers-color-scheme: dark) {
+    body { background: #0f1419; color: #e5e7eb; }
+    .card { background: #1a2332; border-color: #2d3a4d; box-shadow: none; }
+    .status { color: #f3f4f6; }
+    .muted { color: #9ca3af; }
+    .host { background: #243044; color: #d1d5db; }
+  }
+  .card {
+    width: min(32rem, calc(100% - 2rem));
+    padding: 2.5rem 2rem;
+    border-radius: 12px;
+    background: #fff;
+    border: 1px solid #e5e7eb;
+    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.06);
+    text-align: center;
+  }
+  .status {
+    margin: 0;
+    font-size: clamp(3.5rem, 12vw, 5.5rem);
+    font-weight: 700;
+    letter-spacing: -0.04em;
+    line-height: 1;
+    color: #111827;
+  }
+  h1 {
+    margin: 1rem 0 0.5rem;
+    font-size: 1.25rem;
+    font-weight: 600;
+  }
+  p { margin: 0.4rem 0; line-height: 1.6; }
+  .muted { color: #6b7280; font-size: 0.95rem; }
+  .host {
+    display: inline-block;
+    margin-top: 1.25rem;
+    padding: 0.35rem 0.75rem;
+    border-radius: 999px;
+    background: #f3f4f6;
+    color: #374151;
+    font-size: 0.85rem;
+    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+    word-break: break-all;
+  }
+</style>
+</head>
+<body>
+  <main class="card" role="main">
+    <p class="status" aria-label="HTTP status">{{status}}</p>
+    <h1>源站暂时无法提供服务</h1>
+    <p class="muted">网关已拦截源站错误响应。请稍后重试；若问题持续，请联系站点管理员。</p>
+    <p class="host">{{host}}</p>
+  </main>
+</body>
+</html>
+`
+
+// EffectiveOriginErrorPageHTML returns custom HTML when set, otherwise the built-in default.
+func EffectiveOriginErrorPageHTML(cfg ConfigSnapshot) string {
+	if strings.TrimSpace(cfg.OriginErrorPageHTML) == "" {
+		return DefaultOriginErrorPageHTML
+	}
+	return cfg.OriginErrorPageHTML
+}
+
+func effectiveOriginErrorPageStatusTags(cfg ConfigSnapshot) []string {
+	if len(cfg.OriginErrorPageStatusCodes) == 0 {
+		return []string{defaultOriginErrorPageStatusTag}
+	}
+	return cfg.OriginErrorPageStatusCodes
+}
+
+func originErrorPageSupportFile(cfg ConfigSnapshot) SupportFile {
+	return SupportFile{
+		Path:    OriginErrorPageSupportPath,
+		Content: EffectiveOriginErrorPageHTML(cfg),
+	}
+}
+
+func renderOriginErrorPageIntercept(cfg ConfigSnapshot) string {
+	if !cfg.OriginErrorPageEnabled {
+		return ""
+	}
+	if _, err := ExpandStatusCodeTags(effectiveOriginErrorPageStatusTags(cfg)); err != nil {
+		return ""
+	}
+	return "        proxy_intercept_errors on;\n"
+}
+
+// renderOriginErrorPageServerBits emits server-level error_page + internal location.
+// Returns empty string when disabled, expand fails, or no codes remain.
+func renderOriginErrorPageServerBits(cfg ConfigSnapshot) string {
+	if !cfg.OriginErrorPageEnabled {
+		return ""
+	}
+	codes, err := ExpandStatusCodeTags(effectiveOriginErrorPageStatusTags(cfg))
+	if err != nil || len(codes) == 0 {
+		return ""
+	}
+	parts := make([]string, len(codes))
+	for i, code := range codes {
+		parts[i] = strconv.Itoa(code)
+	}
+	var builder strings.Builder
+	fmt.Fprintf(&builder, "    error_page %s = %s;\n", strings.Join(parts, " "), OriginErrorPageInternalLocation)
+	builder.WriteString(renderOriginErrorPageInternalLocation())
+	return builder.String()
+}
+
+func renderOriginErrorPageInternalLocation() string {
+	return fmt.Sprintf(`    location = %s {
+        internal;
+        default_type text/html;
+        charset utf-8;
+        content_by_lua_block {
+            local f = io.open("%s", "r")
+            if not f then
+                ngx.status = ngx.status
+                ngx.say("Error ", ngx.status)
+                return
+            end
+            local body = f:read("*a")
+            f:close()
+            local status = tostring(ngx.status)
+            local host = ngx.var.host or ""
+            body = body:gsub("{{status}}", status, 1)
+            body = body:gsub("{{host}}", host, 1)
+            body = body:gsub("{{status}}", status)
+            body = body:gsub("{{host}}", host)
+            ngx.header["Content-Type"] = "text/html; charset=utf-8"
+            ngx.say(body)
+        }
+    }
+`, OriginErrorPageInternalLocation, ErrorPageTmplPlaceholder)
+}