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import OpenAI from "openai";
import { MAX_TOKENS, RESPONSE_LENGTH } from "./logic/constants";
import type { AResult, ChatMessage, OChoice } from "./types";
type Message = OpenAI.Chat.Completions.ChatCompletionMessageParam;
type Props = {
baseURL: string;
apiKey: string;
model: string;
maxTokens?: number;
tokenizer?: (text: string) => number;
};
export default class Conversation {
private apiKey;
private baseURL;
private maxTokens: number = MAX_TOKENS;
private tokenizer: (text: string) => number = (text) => text.length / 3;
private api;
private model;
constructor(props: Props) {
this.apiKey = props.apiKey;
this.baseURL = props.baseURL;
this.api = new OpenAI({ baseURL: this.baseURL, apiKey: this.apiKey });
this.model = props.model;
if (props.maxTokens) this.maxTokens = props.maxTokens;
if (props.tokenizer) this.tokenizer = props.tokenizer;
}
public setModel(model: string) {
this.model = model;
}
private mapMessages(input: ChatMessage[]): Message[] {
return input.map((m) => {
return { role: m.author as any, content: m.text, name: m.author };
});
}
public async send(sys: string, input: ChatMessage[]): AResult<string[]> {
const messages = this.mapMessages(input);
const sysMsg: Message = { role: "system", content: sys };
const allMessages = [sysMsg, ...messages];
console.log("before truncation", allMessages);
const truncated = this.truncateHistory(allMessages);
const res = await this.apiCall(truncated);
if ("error" in res) return res;
else
try {
return { ok: res.ok.map((c) => c.message.content!) };
} catch (e) {
return { error: `${e}` };
}
}
public async stream(
sys: string,
input: ChatMessage[],
handle: (c: string) => void,
) {
const messages = this.mapMessages(input);
const sysMsg: Message = { role: "system", content: sys };
const allMessages = [sysMsg, ...messages];
const truncated = this.truncateHistory(allMessages);
await this.apiCallStream(truncated, handle);
}
private truncateHistory(messages: Message[]): Message[] {
const totalTokens = messages.reduce((total, message) => {
return total + this.tokenizer(message.content as string);
}, 0);
while (totalTokens > this.maxTokens && messages.length > 1) {
// Always keep the system message if it exists
const startIndex = messages[0].role === "system" ? 1 : 0;
messages.splice(startIndex, 1);
}
return messages;
}
// TODO custom temperature?
private async apiCall(messages: Message[]): AResult<OChoice[]> {
console.log({ messages }, "at the very end");
try {
const completion = await this.api.chat.completions.create({
temperature: 1.3,
model: this.model,
messages,
max_tokens: RESPONSE_LENGTH,
});
if (!completion) return { error: "null response from openai" };
return { ok: completion.choices };
} catch (e) {
console.log(e, "error in openai api");
return { error: `${e}` };
}
}
private async apiCallStream(
messages: Message[],
handle: (c: string) => void,
): Promise<void> {
try {
const stream = await this.api.chat.completions.create({
temperature: 1.3,
model: this.model,
messages,
max_tokens: RESPONSE_LENGTH,
stream: true,
});
for await (const chunk of stream) {
for (const choice of chunk.choices) {
console.log({ choice });
if (!choice.delta) continue;
const cont = choice.delta.content;
if (!cont) continue;
handle(cont);
}
}
} catch (e) {
console.log(e, "error in openai api");
handle(`Error streaming OpenAI, ${e}`);
}
}
}
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