Implement managed browser security, individual agents and observability

apps/browser/history-navigation.cjs

@@ -0,0 +1,27 @@
+'use strict';
+// Native history only: pages and agents cannot supply a navigation target.
+async function performHistory({contents,action,allowed,current,signal,timeoutMs=10000}={}) {
+  if(!contents||!['back','forward','reload'].includes(action)||typeof allowed!=='function'||typeof current!=='function'||!Number.isFinite(timeoutMs)||timeoutMs<1||timeoutMs>60000)throw Error('Invalid history operation');
+  const guard=async(phase='before')=>{if(signal?.aborted)throw Error('History operation cancelled');if(contents.isDestroyed?.())throw Error('History contents unavailable');if(await current(phase)!==true)throw Error('History context changed');if(signal?.aborted)throw Error('History operation cancelled');};
+  const target=()=>action==='reload'?contents.getURL():contents.navigationHistory.getEntryAtIndex(contents.navigationHistory.getActiveIndex()+(action==='back'?-1:1))?.url;
+  await guard();const url=target();
+  if(!url)return {completed:false,url:contents.getURL()};
+  let parsed;try{parsed=new URL(url);}catch{throw Error('Invalid history destination');}
+  if(!['http:','https:'].includes(parsed.protocol)||parsed.username||parsed.password||!await allowed(url))throw Error('History destination denied');
+  await guard();if(target()!==url)throw Error('History destination changed');
+  return new Promise((resolve,reject)=>{
+    let settled=false,dispatched=false,checking=false;
+    const cleanup=()=>{clearTimeout(timer);signal?.removeEventListener('abort',abort);for(const [name,fn] of listeners)contents.removeListener(name,fn);};
+    const fail=error=>{if(settled)return;settled=true;cleanup();if(dispatched&&!contents.isDestroyed?.())try{contents.stop();}catch{}reject(error);};
+    const complete=async()=>{if(!dispatched||settled||checking)return;checking=true;try{await guard('after');if(contents.getURL()!==url)throw Error('History destination changed');if(!await allowed(url))throw Error('History destination denied');await guard('after');if(contents.getURL()!==url)throw Error('History destination changed');if(settled)return;settled=true;cleanup();resolve({completed:true,url});}catch(error){fail(error);}finally{checking=false;}};
+    const inPage=(_event,eventUrl,isMainFrame)=>{if(isMainFrame===true){if(eventUrl!==url)fail(Error('History destination changed'));else void complete();}};
+    const loadFailed=(_event,_code,_description,_url,isMainFrame)=>{if(isMainFrame===true)fail(Error('History navigation failed'));};
+    const abort=()=>fail(Error('History operation cancelled'));
+    const listeners=[['did-finish-load',complete],['did-navigate-in-page',inPage],['did-fail-load',loadFailed],['destroyed',()=>fail(Error('History contents unavailable'))]];
+    const timer=setTimeout(()=>fail(Error('History operation timed out')),timeoutMs);
+    for(const [name,fn] of listeners)contents.on(name,fn);signal?.addEventListener('abort',abort,{once:true});
+    if(signal?.aborted){abort();return;}
+    try{dispatched=true;if(action==='reload')contents.reload();else contents.navigationHistory.goToIndex(contents.navigationHistory.getActiveIndex()+(action==='back'?-1:1));}catch(error){fail(error);}
+  });
+}
+module.exports={performHistory};