{"record":{"id":"512cdb657280f25d","repo":"DioxusLabs/dioxus","slug":"body-element-to-exist","errorCode":null,"errorMessage":"Body element to exist","messagePattern":"Body element to exist","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packages/desktop/src/protocol.rs","lineNumber":129,"sourceCode":" // If the request is for the root, we'll serve the index.html file.\n if request.uri().path() != \"/\" {\n return None;\n }\n\n // Load a custom index file if provided\n let mut index = custom_index.unwrap_or_else(|| DEFAULT_INDEX.to_string());\n\n // Insert a custom head if provided\n // We look just for the closing head tag. If a user provided a custom index with weird syntax, this might fail\n if let Some(head) = custom_head {\n index.insert_str(index.find(\"\").expect(\"Head element to exist\"), &head);\n }\n\n // Inject our module loader by looking for a body tag\n // A failure mode here, obviously, is if the user provided a custom index without a body tag\n // Might want to document this\n index.insert_str(\n index.find(\"\").expect(\"Body element to exist\"),\n &module_loader(root_name, headless, edit_state),\n );\n\n Response::builder()\n .header(\"Content-Type\", \"text/html\")\n .header(\"Access-Control-Allow-Origin\", \"*\")\n .body(index.into())\n .ok()\n}\n\n/// Construct the inline script that boots up the page and bridges the webview with rust code.\n///\n/// The arguments here:\n/// - root_name: the root element (by Id) that we stream edits into\n/// - headless: is this page being loaded but invisible? Important because not all windows are visible and the\n/// interpreter can't connect until the window is ready.\n/// - port: the port that the websocket server is listening on for edits\n/// - webview_id: the id of the webview that we're loading this into. This is used to differentiate between","sourceCodeStart":111,"sourceCodeEnd":147,"githubUrl":"https://github.com/DioxusLabs/dioxus/blob/393d190a801ccb441d41923e232289b4f8a5c669/packages/desktop/src/protocol.rs#L111-L147","documentation":"The desktop protocol injects its JS module loader immediately before ``; find(\"\").expect(\"Body element to exist\") panics when the served index.html has no exact closing body tag. Unlike the head check, this runs on every root request regardless of custom_head.","triggerScenarios":"Supplying a custom index via with_custom_index (or the configured index.html) that lacks `` - e.g. only a fragment like `

` - or uses a case-mismatched ``.","commonSituations":"Replacing index.html with a partial snippet; minified/templated HTML where the body tag got mangled; assuming the framework will wrap fragments automatically.","solutions":["Include a complete HTML document with `...` in the custom index","Ensure the literal lowercase `` is present; the lookup is case-sensitive","Remove the custom index to fall back to dioxus's built-in default index"],"exampleFix":"// before\n.with_custom_index(\"

\".into())\n\n// after\n.with_custom_index(\"

\".into())","handlingStrategy":"validation","validationCode":"fn index_has_body(index: &str) -> bool { index.contains(\"\") }\n\nlet html = std::fs::read_to_string(\"index.html\").unwrap();\nassert!(index_has_body(&html), \"custom index must contain \");","typeGuard":"fn is_valid_custom_index(index: &str) -> bool {\n index.contains(\"\") && index.contains(\"\")\n}","tryCatchPattern":null,"preventionTips":["Never pass HTML fragments as with_custom_index - use a full document","Smoke-test the app startup after every custom index change","Remember both tag lookups are exact, case-sensitive string matches"],"tags":["desktop","index-html","config","panic","runtime"],"backgroundTag":null,"analyzedSha":"393d190a801ccb441d41923e232289b4f8a5c669","analyzedAt":"2026-08-16T11:27:45.815Z","schemaVersion":2},"datasetVersion":"2026-08-16T13:17:31.715Z"}