@langchain/langgraph
Version:
197 lines • 7.96 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.StreamMessagesHandler = void 0;
const base_1 = require("@langchain/core/callbacks/base");
const messages_1 = require("@langchain/core/messages");
const constants_js_1 = require("../constants.cjs");
function isChatGenerationChunk(x) {
return (0, messages_1.isBaseMessage)(x?.message);
}
/**
* A callback handler that implements stream_mode=messages.
* Collects messages from (1) chat model stream events and (2) node outputs.
*/
// TODO: Make this import and explicitly implement the
// CallbackHandlerPrefersStreaming interface once we drop support for core 0.2
class StreamMessagesHandler extends base_1.BaseCallbackHandler {
constructor(streamFn) {
super();
Object.defineProperty(this, "name", {
enumerable: true,
configurable: true,
writable: true,
value: "StreamMessagesHandler"
});
Object.defineProperty(this, "streamFn", {
enumerable: true,
configurable: true,
writable: true,
value: void 0
});
Object.defineProperty(this, "metadatas", {
enumerable: true,
configurable: true,
writable: true,
value: {}
});
Object.defineProperty(this, "seen", {
enumerable: true,
configurable: true,
writable: true,
value: {}
});
Object.defineProperty(this, "emittedChatModelRunIds", {
enumerable: true,
configurable: true,
writable: true,
value: {}
});
Object.defineProperty(this, "stableMessageIdMap", {
enumerable: true,
configurable: true,
writable: true,
value: {}
});
Object.defineProperty(this, "lc_prefer_streaming", {
enumerable: true,
configurable: true,
writable: true,
value: true
});
this.streamFn = streamFn;
}
_emit(meta, message, runId, dedupe = false) {
if (dedupe &&
message.id !== undefined &&
this.seen[message.id] !== undefined) {
return;
}
let messageId = message.id;
if (runId != null) {
if ((0, messages_1.isToolMessage)(message)) {
// Distinguish tool messages by tool call ID.
messageId ??= `run-${runId}-tool-${message.tool_call_id}`;
}
else {
// For instance in ChatAnthropic, the first chunk has an message ID
// but the subsequent chunks do not. To avoid clients seeing two messages
// we rename the message ID if it's being auto-set to `run-${runId}`
// (see https://github.com/langchain-ai/langchainjs/pull/6646).
if (messageId == null || messageId === `run-${runId}`) {
messageId =
this.stableMessageIdMap[runId] ?? messageId ?? `run-${runId}`;
}
this.stableMessageIdMap[runId] ??= messageId;
}
}
if (messageId !== message.id) {
// eslint-disable-next-line no-param-reassign
message.id = messageId;
// eslint-disable-next-line no-param-reassign
message.lc_kwargs.id = messageId;
}
if (message.id != null)
this.seen[message.id] = message;
this.streamFn([meta[0], "messages", [message, meta[1]]]);
}
handleChatModelStart(_llm, _messages, runId, _parentRunId, _extraParams, tags, metadata, name) {
if (metadata &&
// Include legacy LangGraph SDK tag
(!tags || (!tags.includes(constants_js_1.TAG_NOSTREAM) && !tags.includes("nostream")))) {
this.metadatas[runId] = [
metadata.langgraph_checkpoint_ns.split("|"),
{ tags, name, ...metadata },
];
}
}
handleLLMNewToken(token, _idx, runId, _parentRunId, _tags, fields) {
const chunk = fields?.chunk;
this.emittedChatModelRunIds[runId] = true;
if (this.metadatas[runId] !== undefined) {
if (isChatGenerationChunk(chunk)) {
this._emit(this.metadatas[runId], chunk.message, runId);
}
else {
this._emit(this.metadatas[runId], new messages_1.AIMessageChunk({ content: token }), runId);
}
}
}
handleLLMEnd(output, runId) {
// In JS, non-streaming runs do not call handleLLMNewToken at the model level
if (!this.emittedChatModelRunIds[runId]) {
const chatGeneration = output.generations?.[0]?.[0];
if ((0, messages_1.isBaseMessage)(chatGeneration?.message)) {
this._emit(this.metadatas[runId], chatGeneration?.message, runId, true);
}
delete this.emittedChatModelRunIds[runId];
}
delete this.metadatas[runId];
delete this.stableMessageIdMap[runId];
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any
handleLLMError(_err, runId) {
delete this.metadatas[runId];
}
handleChainStart(_chain, inputs, runId, _parentRunId, tags, metadata, _runType, name) {
if (metadata !== undefined &&
name === metadata.langgraph_node &&
(tags === undefined || !tags.includes(constants_js_1.TAG_HIDDEN))) {
this.metadatas[runId] = [
metadata.langgraph_checkpoint_ns.split("|"),
{ tags, name, ...metadata },
];
if (typeof inputs === "object") {
for (const value of Object.values(inputs)) {
if (((0, messages_1.isBaseMessage)(value) || (0, messages_1.isBaseMessageChunk)(value)) &&
value.id !== undefined) {
this.seen[value.id] = value;
}
else if (Array.isArray(value)) {
for (const item of value) {
if (((0, messages_1.isBaseMessage)(item) || (0, messages_1.isBaseMessageChunk)(item)) &&
item.id !== undefined) {
this.seen[item.id] = item;
}
}
}
}
}
}
}
handleChainEnd(outputs, runId) {
const metadata = this.metadatas[runId];
delete this.metadatas[runId];
if (metadata !== undefined) {
if ((0, messages_1.isBaseMessage)(outputs)) {
this._emit(metadata, outputs, runId, true);
}
else if (Array.isArray(outputs)) {
for (const value of outputs) {
if ((0, messages_1.isBaseMessage)(value)) {
this._emit(metadata, value, runId, true);
}
}
}
else if (outputs != null && typeof outputs === "object") {
for (const value of Object.values(outputs)) {
if ((0, messages_1.isBaseMessage)(value)) {
this._emit(metadata, value, runId, true);
}
else if (Array.isArray(value)) {
for (const item of value) {
if ((0, messages_1.isBaseMessage)(item)) {
this._emit(metadata, item, runId, true);
}
}
}
}
}
}
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any
handleChainError(_err, runId) {
delete this.metadatas[runId];
}
}
exports.StreamMessagesHandler = StreamMessagesHandler;
//# sourceMappingURL=messages.js.map