ErrLookup › aio-libs/aiohttp
aio-libs/aiohttp
Asynchronous HTTP client/server framework for asyncio and Python · Python · 60 source files
Analyzed at d041d4d0fd on 2026-08-11. 203 documented errors.
| Code / Message | Type | Severity | Tags |
|---|---|---|---|
1002 Continuation frame for non started message | exception | error | websocket, protocol-error, rfc6455, continuation, server, client |
| The first argument should be web.Application instance, got | exception | error | web-server, app-runner, configuration, type-check |
| Cannot initialize a TLS-in-TLS connection to host | exception | error | ssl, proxy, tls-in-tls, python-version, event-loop |
| Only async functions are allowed as web-handlers, got | exception | error | routing, handler, async, type-check |
| Unknown Expect | http | warning | http, expect-header, client-error, http-417 |
| unknown content transfer encoding | exception | error | multipart, mime, headers, validation |
| Connection lost | exception | error | network, connection-reset, flow-control, drain, transport |
| The brotli decompression is not available. Please install… | exception | error | decompression, dependency, brotli, runtime-error |
| - is not a canonical IPv4 address | exception | error | url, security, ssrf, ip-validation, invalid-url |
| Cannot connect to host | exception | error | ssl, connection, handshake, client-connector |
| No WebSocket UPGRADE hdr | http | error | websocket, handshake, http-upgrade, proxy |
| total timeout must be a positive number or None to disable… | validation | error | timeout, configuration, client, version-migration |
| Cannot connect to host | exception | error | ssl, certificate, connection, client-connector |
| Cannot change apps stack after .freeze() call | exception | error | routing, lifecycle, freeze, sub-app |
1007 Invalid UTF-8 text message | exception | error | websocket, utf-8, text-frame, rfc6455, validation, invalid-text |
| DNS lookup failed | exception | error | dns, network, resolver, oserror |
| Failed to get module name. | exception | error | app-key, introspection, runtime-error, application, initialization |
| Incorrect route name | validation | error | url-dispatcher, route-naming, validation, identifiers |
| Malformed Digest auth challenge: Missing 'realm' parameter | exception | error | digest-auth, authentication, http, client-middleware |
| Cannot register a resource into frozen router. | exception | error | url-dispatcher, frozen-router, lifecycle, runtime |
| The zstd decompression is not available. Please install… | exception | error | decompression, dependency, zstd, runtime-error |
| Unsupported order | validation | error | payload, registry, enum, api-misuse |
| Duplicate ' ' header found. | exception | error | http, parser, header, security, validation |
| Invalid path ' '[' '] | exception | error | routing, path-template, validation |
| is not allowed HTTP method | exception | error | routing, validation, http-method |
| Added route will never be executed, method | exception | error | routing, duplicate, registration |
1009 Compressed message has too many deflate members | exception | error | websocket, permessage-deflate, security, zip-bomb, message-too-big, rfc7692 |
| ClientHttpProxyError | exception | error | proxy, connection, authentication, client-connector |
| {path} | exception | error | http-parser, request-line, rfc-9112, invalid-url |
| Cannot compute fallback encoding of a not yet read body | exception | error | client, response, encoding, usage |
| access_log_class must be subclass of… | exception | error | web-server, app-runner, access-log, type-check |
| Compressed stream has more than | exception | error | decompression, security, dos, zstd, brotli |
| Digest auth error: Unsupported Quality of Protection (qop)… | exception | error | digest-auth, authentication, http, client-middleware, qop |
| Already started | exception | error | websocket, lifecycle, state, programmer-error |
| compress can not be set if Content-Encoding header is set | exception | error | client, request, compression, http-headers, configuration |
| data argument must be byte-ish (%r) | exception | error | websocket, typing, send, typeerror |
| Not enough data to satisfy transfer length header. | http | error | http-parser, transfer-encoding, chunked, truncated, payload |
| Scheme not supported | exception | error | url-dispatcher, domain-routing, config, validation |
| Attempt to decode JSON with unexpected mimetype | exception | error | client, response, json, content-type, http |
| keepalive_timeout cannot be set if force_close is True | exception | error | connector, configuration, value-error, tcp-connector |
| Connection closed | exception | error | client, response, lifecycle, connection, usage |
| Cannot write to closing transport | exception | error | websocket, writer, closing, connection-reset, race-condition |
| No CONNECTION upgrade hdr | http | error | websocket, handshake, proxy, http-headers |
| Domain not valid | exception | error | url-dispatcher, domain-routing, validation, dns |
| invalid Content-Length | validation | error | multipart, http-headers, content-length, validation, rfc-9110 |
| Got more than bytes when reading: . | exception | error | streams, limits, parsing, memory |
| Use Python 3.11+ to run 'make sync-direct-runtime-deps' | exception | error | build, tooling, python-version, dependencies, maintenance |
| EmptyStreamReader._on_chunk_received is read-only | validation | error | streams, singleton, observability, api-misuse |
| Concurrent call to receive() is not allowed | exception | error | websocket, client, concurrency, runtime-error |
| Bad pattern | exception | error | routing, regex, path-template, validation |
| Value is not a valid etag. Maybe it contains '"'? | exception | error | http, etag, validation, header, server |
| Cannot add frozen application | exception | error | web, subapp, lifecycle, frozen |
| Extension for deflate not supported | exception | error | websocket, handshake, compression, deflate, extension |
| 404: Not Found | http | warning | static-files, security, path-traversal, http-404 |
| Inheritance class from web.Application is forbidden | validation | error | web, application, design, api-misuse |
| Changing state of started or joined application is forbidden | exception | error | web, application, lifecycle, state |
| Digest auth error: Unsupported hash algorithm | exception | error | digest-auth, authentication, http, client-middleware, cryptography |
| Method cannot contain non-token characters | exception | error | client, request, security, validation, http-method |
| 403: Forbidden | http | warning | static-files, directory-listing, security, http-403 |
| Gunicorn's style options in form of `%(name)s` are not… | validation | error | gunicorn, logging, configuration, boot, deployment |
| Invalid Content-Length header | exception | error | client, request, http-headers, validation, content-length |
| Forbidden control character detected in headers. Potential… | validation | error | http-writer, header-injection, security, crlf-injection, validation |
| Multiple errors on cleanup stage | exception | error | lifecycle, cleanup, shutdown, runtime-error |
| Invalid window size | exception | error | websocket, handshake, compression, deflate, window-bits |
| deflate | http | error | content-encoding, deflate, decompression, truncated, zlib |
| Not enough data to satisfy content length header | exception | error | http-parser, content-length, payload, truncated, body |
| Connector is closed. | exception | error | connector, lifecycle, concurrency, client-connection-error |
| Unsupported type for last_modified | validation | error | aiohttp, web-response, last-modified, datetime, type-error |
| Received message : is not WSMsgType.TEXT | exception | error | websocket, client, message-type, receive-str |
| Cannot call .write() for websocket | exception | error | websocket, send, api-misuse, server |
| Duplicate , already handled by | validation | error | url-dispatcher, route-naming, duplicate, url-building |
| Malformed Digest auth challenge: Missing 'nonce' parameter | exception | error | digest-auth, authentication, http, client-middleware |
| aiohttp 4.x requires Python 3.10+ | exception | error | install, python-version, build, upgrade |
| Connection closed. | exception | error | streams, connection, lifecycle, network |
| OPTIONS route was set already | exception | error | static-files, options, duplicate, configuration |
| Setting charset for application/octet-stream doesn't make… | exception | error | aiohttp, web-response, content-type, charset, http-headers |
| Connection timeout to host | exception | error | network, timeout, client, connection, configuration |
| Request has invalid `Transfer-Encoding` | exception | error | http-parser, transfer-encoding, chunked, rfc-9112 |
| Response has not been started | exception | error | websocket, lifecycle, eof, server |
| Request has duplicate `chunked` Transfer-Encoding | exception | error | http-parser, transfer-encoding, chunked, rfc-9112, security |
| wsgi app should be either Application or async function… | exception | error | gunicorn, worker, deployment, typing, boot |
| chunked can not be set if "Transfer-Encoding: chunked"… | exception | error | client, request, http-headers, transfer-encoding, chunked |
| Can not decode content-encoding: brotli (br). Please… | http | error | content-encoding, brotli, decompression, missing-dependency, optional-deps |
| Can not decode content-encoding | http | error | content-encoding, decompression, corruption, gzip, deflate |
| compress must be one of True, False, 'deflate', or 'gzip' | exception | error | client, request, compression, validation, configuration |
| path should be started with / or be empty | validation | error | url-dispatcher, path-routing, validation |
| module has no attribute | exception | error | api, import, version-migration, attribute-error |
| KeyError | exception | error | chainmap-proxy, key-error, application, storage, request |
| Incorrect route name | validation | error | url-dispatcher, route-naming, validation, identifiers |
| boundary value contains invalid characters | validation | error | multipart, boundary, validation, rfc-2046, content-type, writer |
| value argument must be byte-ish, not | exception | error | payload, type-error, bytes, serialization |
| aiohttp only supports http(s) proxies | exception | error | client, proxy, configuration, http, socks |
| Connector is closed | exception | error | connector, lifecycle, dns, client-connection-error |
| Called while some coroutine is waiting for incoming data. | exception | error | streams, concurrency, sync, api-misuse |
| () called while another coroutine is already waiting for… | exception | error | streams, concurrency, async, api-misuse |
| base_url must have a trailing '/' | validation | error | client-session, configuration, url, validation |
| Can not decode content-encoding: zstandard (zstd). Please… | http | error | content-encoding, zstd, decompression, missing-dependency, optional-deps |
| Domain cannot be empty | exception | error | routing, domain, validation, configuration |
| Too many trailers received | http | error | http-parser, trailers, chunked, limits, resource-exhaustion |
| data argument must be str (%r) | exception | error | websocket, send-str, type-error, validation |