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chat.ts
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// Default generic "any" values are for backwards compatibility.
// Replace with "string" when we are comfortable with a breaking change.
import type { BaseCallbackConfig } from "../callbacks/manager.js";
import {
AIMessage,
HumanMessage,
SystemMessage,
BaseMessage,
ChatMessage,
type BaseMessageLike,
coerceMessageLikeToMessage,
isBaseMessage,
MessageContent,
} from "../messages/index.js";
import {
type ChatPromptValueInterface,
ChatPromptValue,
} from "../prompt_values.js";
import type { InputValues, PartialValues } from "../utils/types/index.js";
import { Runnable } from "../runnables/base.js";
import { BaseStringPromptTemplate } from "./string.js";
import {
BasePromptTemplate,
type BasePromptTemplateInput,
type TypedPromptInputValues,
} from "./base.js";
import {
PromptTemplate,
type ParamsFromFString,
PromptTemplateInput,
ExtractedFStringParams,
} from "./prompt.js";
import { ImagePromptTemplate } from "./image.js";
import {
ParsedTemplateNode,
TemplateFormat,
parseFString,
parseMustache,
} from "./template.js";
/**
* Abstract class that serves as a base for creating message prompt
* templates. It defines how to format messages for different roles in a
* conversation.
*/
export abstract class BaseMessagePromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any,
RunOutput extends BaseMessage[] = BaseMessage[]
> extends Runnable<RunInput, RunOutput> {
lc_namespace = ["langchain_core", "prompts", "chat"];
lc_serializable = true;
abstract inputVariables: Array<Extract<keyof RunInput, string>>;
/**
* Method that takes an object of TypedPromptInputValues and returns a
* promise that resolves to an array of BaseMessage instances.
* @param values Object of TypedPromptInputValues
* @returns Formatted array of BaseMessages
*/
abstract formatMessages(
values: TypedPromptInputValues<RunInput>
): Promise<RunOutput>;
/**
* Calls the formatMessages method with the provided input and options.
* @param input Input for the formatMessages method
* @param options Optional BaseCallbackConfig
* @returns Formatted output messages
*/
async invoke(
input: RunInput,
options?: BaseCallbackConfig
): Promise<RunOutput> {
return this._callWithConfig(
(input: RunInput) => this.formatMessages(input),
input,
{ ...options, runType: "prompt" }
);
}
}
/**
* Interface for the fields of a MessagePlaceholder.
*/
export interface MessagesPlaceholderFields<T extends string> {
variableName: T;
optional?: boolean;
}
/**
* Class that represents a placeholder for messages in a chat prompt. It
* extends the BaseMessagePromptTemplate.
*/
export class MessagesPlaceholder<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any
>
extends BaseMessagePromptTemplate<RunInput>
implements MessagesPlaceholderFields<Extract<keyof RunInput, string>>
{
static lc_name() {
return "MessagesPlaceholder";
}
variableName: Extract<keyof RunInput, string>;
optional: boolean;
constructor(variableName: Extract<keyof RunInput, string>);
constructor(
fields: MessagesPlaceholderFields<Extract<keyof RunInput, string>>
);
constructor(
fields:
| Extract<keyof RunInput, string>
| MessagesPlaceholderFields<Extract<keyof RunInput, string>>
) {
if (typeof fields === "string") {
// eslint-disable-next-line no-param-reassign
fields = { variableName: fields };
}
super(fields);
this.variableName = fields.variableName;
this.optional = fields.optional ?? false;
}
get inputVariables() {
return [this.variableName];
}
validateInputOrThrow(
input: Array<unknown> | undefined,
variableName: Extract<keyof RunInput, string>
): input is BaseMessage[] {
if (this.optional && !input) {
return false;
} else if (!input) {
const error = new Error(
`Error: Field "${variableName}" in prompt uses a MessagesPlaceholder, which expects an array of BaseMessages as an input value. Received: undefined`
);
error.name = "InputFormatError";
throw error;
}
let isInputBaseMessage = false;
if (Array.isArray(input)) {
isInputBaseMessage = input.every((message) =>
isBaseMessage(message as BaseMessage)
);
} else {
isInputBaseMessage = isBaseMessage(input as BaseMessage);
}
if (!isInputBaseMessage) {
const readableInput =
typeof input === "string" ? input : JSON.stringify(input, null, 2);
const error = new Error(
`Error: Field "${variableName}" in prompt uses a MessagesPlaceholder, which expects an array of BaseMessages as an input value. Received: ${readableInput}`
);
error.name = "InputFormatError";
throw error;
}
return true;
}
async formatMessages(
values: TypedPromptInputValues<RunInput>
): Promise<BaseMessage[]> {
this.validateInputOrThrow(values[this.variableName], this.variableName);
return values[this.variableName] ?? [];
}
}
/**
* Interface for the fields of a MessageStringPromptTemplate.
*/
export interface MessageStringPromptTemplateFields<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
T extends InputValues = any
> {
prompt: BaseStringPromptTemplate<T, string>;
}
/**
* Abstract class that serves as a base for creating message string prompt
* templates. It extends the BaseMessagePromptTemplate.
*/
export abstract class BaseMessageStringPromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any
> extends BaseMessagePromptTemplate<RunInput> {
prompt: BaseStringPromptTemplate<
InputValues<Extract<keyof RunInput, string>>,
string
>;
constructor(
prompt: BaseStringPromptTemplate<
InputValues<Extract<keyof RunInput, string>>
>
);
constructor(
fields: MessageStringPromptTemplateFields<
InputValues<Extract<keyof RunInput, string>>
>
);
constructor(
fields:
| MessageStringPromptTemplateFields<
InputValues<Extract<keyof RunInput, string>>
>
| BaseStringPromptTemplate<
InputValues<Extract<keyof RunInput, string>>,
string
>
) {
if (!("prompt" in fields)) {
// eslint-disable-next-line no-param-reassign
fields = { prompt: fields };
}
super(fields);
this.prompt = fields.prompt;
}
get inputVariables() {
return this.prompt.inputVariables;
}
abstract format(
values: TypedPromptInputValues<RunInput>
): Promise<BaseMessage>;
async formatMessages(
values: TypedPromptInputValues<RunInput>
): Promise<BaseMessage[]> {
return [await this.format(values)];
}
}
/**
* Abstract class that serves as a base for creating chat prompt
* templates. It extends the BasePromptTemplate.
*/
export abstract class BaseChatPromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any,
// eslint-disable-next-line @typescript-eslint/no-explicit-any
PartialVariableName extends string = any
> extends BasePromptTemplate<
RunInput,
ChatPromptValueInterface,
PartialVariableName
> {
constructor(input: BasePromptTemplateInput<RunInput, PartialVariableName>) {
super(input);
}
abstract formatMessages(
values: TypedPromptInputValues<RunInput>
): Promise<BaseMessage[]>;
async format(values: TypedPromptInputValues<RunInput>): Promise<string> {
return (await this.formatPromptValue(values)).toString();
}
async formatPromptValue(
values: TypedPromptInputValues<RunInput>
): Promise<ChatPromptValueInterface> {
const resultMessages = await this.formatMessages(values);
return new ChatPromptValue(resultMessages);
}
}
/**
* Interface for the fields of a ChatMessagePromptTemplate.
*/
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export interface ChatMessagePromptTemplateFields<T extends InputValues = any>
extends MessageStringPromptTemplateFields<T> {
role: string;
}
/**
* Class that represents a chat message prompt template. It extends the
* BaseMessageStringPromptTemplate.
*/
export class ChatMessagePromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any
> extends BaseMessageStringPromptTemplate<RunInput> {
static lc_name() {
return "ChatMessagePromptTemplate";
}
role: string;
constructor(
prompt: BaseStringPromptTemplate<
InputValues<Extract<keyof RunInput, string>>
>,
role: string
);
constructor(
fields: ChatMessagePromptTemplateFields<
InputValues<Extract<keyof RunInput, string>>
>
);
constructor(
fields:
| ChatMessagePromptTemplateFields<
InputValues<Extract<keyof RunInput, string>>
>
| BaseStringPromptTemplate<InputValues<Extract<keyof RunInput, string>>>,
role?: string
) {
if (!("prompt" in fields)) {
// eslint-disable-next-line no-param-reassign, @typescript-eslint/no-non-null-assertion
fields = { prompt: fields, role: role! };
}
super(fields);
this.role = fields.role;
}
async format(values: RunInput): Promise<BaseMessage> {
return new ChatMessage(await this.prompt.format(values), this.role);
}
static fromTemplate(
template: string,
role: string,
options?: { templateFormat?: TemplateFormat }
) {
return new this(
PromptTemplate.fromTemplate(template, {
templateFormat: options?.templateFormat,
}),
role
);
}
}
interface _TextTemplateParam {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
text?: string | Record<string, any>;
}
interface _ImageTemplateParam {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
image_url?: string | Record<string, any>;
}
type MessageClass =
| typeof HumanMessage
| typeof AIMessage
| typeof SystemMessage;
type ChatMessageClass = typeof ChatMessage;
interface _StringImageMessagePromptTemplateOptions<
Format extends TemplateFormat = TemplateFormat
> extends Record<string, unknown> {
templateFormat?: Format;
}
class _StringImageMessagePromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any,
RunOutput extends BaseMessage[] = BaseMessage[]
> extends BaseMessagePromptTemplate<RunInput, RunOutput> {
lc_namespace = ["langchain_core", "prompts", "chat"];
lc_serializable = true;
inputVariables: Array<Extract<keyof RunInput, string>> = [];
additionalOptions: _StringImageMessagePromptTemplateOptions = {};
prompt:
| BaseStringPromptTemplate<
InputValues<Extract<keyof RunInput, string>>,
string
>
| Array<
| BaseStringPromptTemplate<
InputValues<Extract<keyof RunInput, string>>,
string
>
| ImagePromptTemplate<
InputValues<Extract<keyof RunInput, string>>,
string
>
| MessageStringPromptTemplateFields<
InputValues<Extract<keyof RunInput, string>>
>
>;
protected messageClass?: MessageClass;
static _messageClass(): MessageClass {
throw new Error(
"Can not invoke _messageClass from inside _StringImageMessagePromptTemplate"
);
}
// ChatMessage contains role field, others don't.
// Because of this, we have a separate class property for ChatMessage.
protected chatMessageClass?: ChatMessageClass;
constructor(
/** @TODO When we come up with a better way to type prompt templates, fix this */
// eslint-disable-next-line @typescript-eslint/no-explicit-any
fields: any,
additionalOptions?: _StringImageMessagePromptTemplateOptions
) {
if (!("prompt" in fields)) {
// eslint-disable-next-line no-param-reassign
fields = { prompt: fields };
}
super(fields);
this.prompt = fields.prompt;
if (Array.isArray(this.prompt)) {
let inputVariables: Extract<keyof RunInput, string>[] = [];
this.prompt.forEach((prompt) => {
if ("inputVariables" in prompt) {
inputVariables = inputVariables.concat(prompt.inputVariables);
}
});
this.inputVariables = inputVariables;
} else {
this.inputVariables = this.prompt.inputVariables;
}
this.additionalOptions = additionalOptions ?? this.additionalOptions;
}
createMessage(content: MessageContent) {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
const constructor = this.constructor as any;
if (constructor._messageClass()) {
const MsgClass = constructor._messageClass();
return new MsgClass({ content });
} else if (constructor.chatMessageClass) {
const MsgClass = constructor.chatMessageClass();
// Assuming ChatMessage constructor also takes a content argument
return new MsgClass({
content,
role: this.getRoleFromMessageClass(MsgClass.lc_name()),
});
} else {
throw new Error("No message class defined");
}
}
getRoleFromMessageClass(name: string) {
switch (name) {
case "HumanMessage":
return "human";
case "AIMessage":
return "ai";
case "SystemMessage":
return "system";
case "ChatMessage":
return "chat";
default:
throw new Error("Invalid message class name");
}
}
static fromTemplate(
template: string | Array<string | _TextTemplateParam | _ImageTemplateParam>,
additionalOptions?: _StringImageMessagePromptTemplateOptions
) {
if (typeof template === "string") {
return new this(PromptTemplate.fromTemplate(template, additionalOptions));
}
const prompt: Array<
PromptTemplate<InputValues> | ImagePromptTemplate<InputValues>
> = [];
for (const item of template) {
if (
typeof item === "string" ||
(typeof item === "object" && "text" in item)
) {
let text = "";
if (typeof item === "string") {
text = item;
} else if (typeof item.text === "string") {
text = item.text ?? "";
}
prompt.push(PromptTemplate.fromTemplate(text, additionalOptions));
} else if (typeof item === "object" && "image_url" in item) {
let imgTemplate = item.image_url ?? "";
let imgTemplateObject: ImagePromptTemplate<InputValues>;
let inputVariables: string[] = [];
if (typeof imgTemplate === "string") {
let parsedTemplate: ParsedTemplateNode[];
if (additionalOptions?.templateFormat === "mustache") {
parsedTemplate = parseMustache(imgTemplate);
} else {
parsedTemplate = parseFString(imgTemplate);
}
const variables = parsedTemplate.flatMap((item) =>
item.type === "variable" ? [item.name] : []
);
if ((variables?.length ?? 0) > 0) {
if (variables.length > 1) {
throw new Error(
`Only one format variable allowed per image template.\nGot: ${variables}\nFrom: ${imgTemplate}`
);
}
inputVariables = [variables[0]];
} else {
inputVariables = [];
}
imgTemplate = { url: imgTemplate };
imgTemplateObject = new ImagePromptTemplate<InputValues>({
template: imgTemplate,
inputVariables,
});
} else if (typeof imgTemplate === "object") {
if ("url" in imgTemplate) {
let parsedTemplate: ParsedTemplateNode[];
if (additionalOptions?.templateFormat === "mustache") {
parsedTemplate = parseMustache(imgTemplate.url);
} else {
parsedTemplate = parseFString(imgTemplate.url);
}
inputVariables = parsedTemplate.flatMap((item) =>
item.type === "variable" ? [item.name] : []
);
} else {
inputVariables = [];
}
imgTemplateObject = new ImagePromptTemplate<InputValues>({
template: imgTemplate,
inputVariables,
});
} else {
throw new Error("Invalid image template");
}
prompt.push(imgTemplateObject);
}
}
return new this({ prompt, additionalOptions });
}
async format(input: TypedPromptInputValues<RunInput>): Promise<BaseMessage> {
// eslint-disable-next-line no-instanceof/no-instanceof
if (this.prompt instanceof BaseStringPromptTemplate) {
const text = await this.prompt.format(input);
return this.createMessage(text);
} else {
const content: MessageContent = [];
for (const prompt of this.prompt) {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
let inputs: Record<string, any> = {};
if (!("inputVariables" in prompt)) {
throw new Error(
`Prompt ${prompt} does not have inputVariables defined.`
);
}
for (const item of prompt.inputVariables) {
if (!inputs) {
inputs = { [item]: input[item] };
}
inputs = { ...inputs, [item]: input[item] };
}
// eslint-disable-next-line no-instanceof/no-instanceof
if (prompt instanceof BaseStringPromptTemplate) {
const formatted = await prompt.format(
inputs as TypedPromptInputValues<RunInput>
);
content.push({ type: "text", text: formatted });
/** @TODO replace this */
// eslint-disable-next-line no-instanceof/no-instanceof
} else if (prompt instanceof ImagePromptTemplate) {
const formatted = await prompt.format(
inputs as TypedPromptInputValues<RunInput>
);
content.push({ type: "image_url", image_url: formatted });
}
}
return this.createMessage(content);
}
}
async formatMessages(values: RunInput): Promise<RunOutput> {
return [await this.format(values)] as BaseMessage[] as RunOutput;
}
}
/**
* Class that represents a human message prompt template. It extends the
* BaseMessageStringPromptTemplate.
* @example
* ```typescript
* const message = HumanMessagePromptTemplate.fromTemplate("{text}");
* const formatted = await message.format({ text: "Hello world!" });
*
* const chatPrompt = ChatPromptTemplate.fromMessages([message]);
* const formattedChatPrompt = await chatPrompt.invoke({
* text: "Hello world!",
* });
* ```
*/
export class HumanMessagePromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any
> extends _StringImageMessagePromptTemplate<RunInput> {
static _messageClass(): typeof HumanMessage {
return HumanMessage;
}
static lc_name() {
return "HumanMessagePromptTemplate";
}
}
/**
* Class that represents an AI message prompt template. It extends the
* BaseMessageStringPromptTemplate.
*/
export class AIMessagePromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any
> extends _StringImageMessagePromptTemplate<RunInput> {
static _messageClass(): typeof AIMessage {
return AIMessage;
}
static lc_name() {
return "AIMessagePromptTemplate";
}
}
/**
* Class that represents a system message prompt template. It extends the
* BaseMessageStringPromptTemplate.
* @example
* ```typescript
* const message = SystemMessagePromptTemplate.fromTemplate("{text}");
* const formatted = await message.format({ text: "Hello world!" });
*
* const chatPrompt = ChatPromptTemplate.fromMessages([message]);
* const formattedChatPrompt = await chatPrompt.invoke({
* text: "Hello world!",
* });
* ```
*/
export class SystemMessagePromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any
> extends _StringImageMessagePromptTemplate<RunInput> {
static _messageClass(): typeof SystemMessage {
return SystemMessage;
}
static lc_name() {
return "SystemMessagePromptTemplate";
}
}
/**
* Interface for the input of a ChatPromptTemplate.
*/
export interface ChatPromptTemplateInput<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any,
// eslint-disable-next-line @typescript-eslint/no-explicit-any
PartialVariableName extends string = any
> extends BasePromptTemplateInput<RunInput, PartialVariableName> {
/**
* The prompt messages
*/
promptMessages: Array<BaseMessagePromptTemplate | BaseMessage>;
/**
* Whether to try validating the template on initialization
*
* @defaultValue `true`
*/
validateTemplate?: boolean;
/**
* The formatting method to use on the prompt.
* @default "f-string"
*/
templateFormat?: TemplateFormat;
}
export type BaseMessagePromptTemplateLike =
| BaseMessagePromptTemplate
| BaseMessageLike;
function _isBaseMessagePromptTemplate(
baseMessagePromptTemplateLike: BaseMessagePromptTemplateLike
): baseMessagePromptTemplateLike is BaseMessagePromptTemplate {
return (
typeof (baseMessagePromptTemplateLike as BaseMessagePromptTemplate)
.formatMessages === "function"
);
}
function _coerceMessagePromptTemplateLike<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any,
Extra extends Omit<
ChatPromptTemplateInput<RunInput>,
"inputVariables" | "promptMessages" | "partialVariables"
> = Omit<
ChatPromptTemplateInput<RunInput>,
"inputVariables" | "promptMessages" | "partialVariables"
>
>(
messagePromptTemplateLike: BaseMessagePromptTemplateLike,
extra?: Extra
): BaseMessagePromptTemplate | BaseMessage {
if (
_isBaseMessagePromptTemplate(messagePromptTemplateLike) ||
isBaseMessage(messagePromptTemplateLike)
) {
return messagePromptTemplateLike;
}
if (
Array.isArray(messagePromptTemplateLike) &&
messagePromptTemplateLike[0] === "placeholder"
) {
const messageContent = messagePromptTemplateLike[1];
if (
typeof messageContent !== "string" ||
messageContent[0] !== "{" ||
messageContent[messageContent.length - 1] !== "}"
) {
throw new Error(
`Invalid placeholder template: "${messagePromptTemplateLike[1]}". Expected a variable name surrounded by curly braces.`
);
}
const variableName = messageContent.slice(1, -1);
return new MessagesPlaceholder({ variableName, optional: true });
}
const message = coerceMessageLikeToMessage(messagePromptTemplateLike);
let templateData:
| string
| (
| string
| _TextTemplateParam
| _ImageTemplateParam
// eslint-disable-next-line @typescript-eslint/no-explicit-any
| Record<string, any>
)[];
if (typeof message.content === "string") {
templateData = message.content;
} else {
// Assuming message.content is an array of complex objects, transform it.
templateData = message.content.map((item) => {
if ("text" in item) {
return { text: item.text };
} else if ("image_url" in item) {
return { image_url: item.image_url };
} else {
return item;
}
});
}
if (message._getType() === "human") {
return HumanMessagePromptTemplate.fromTemplate(templateData, extra);
} else if (message._getType() === "ai") {
return AIMessagePromptTemplate.fromTemplate(templateData, extra);
} else if (message._getType() === "system") {
return SystemMessagePromptTemplate.fromTemplate(templateData, extra);
} else if (ChatMessage.isInstance(message)) {
return ChatMessagePromptTemplate.fromTemplate(
message.content as string,
message.role,
extra
);
} else {
throw new Error(
`Could not coerce message prompt template from input. Received message type: "${message._getType()}".`
);
}
}
function isMessagesPlaceholder(
x: BaseMessagePromptTemplate | BaseMessage
): x is MessagesPlaceholder {
// eslint-disable-next-line @typescript-eslint/no-explicit-any
return (x.constructor as any).lc_name() === "MessagesPlaceholder";
}
/**
* Class that represents a chat prompt. It extends the
* BaseChatPromptTemplate and uses an array of BaseMessagePromptTemplate
* instances to format a series of messages for a conversation.
* @example
* ```typescript
* const message = SystemMessagePromptTemplate.fromTemplate("{text}");
* const chatPrompt = ChatPromptTemplate.fromMessages([
* ["ai", "You are a helpful assistant."],
* message,
* ]);
* const formattedChatPrompt = await chatPrompt.invoke({
* text: "Hello world!",
* });
* ```
*/
export class ChatPromptTemplate<
// eslint-disable-next-line @typescript-eslint/no-explicit-any
RunInput extends InputValues = any,
// eslint-disable-next-line @typescript-eslint/no-explicit-any
PartialVariableName extends string = any
>
extends BaseChatPromptTemplate<RunInput, PartialVariableName>
implements ChatPromptTemplateInput<RunInput, PartialVariableName>
{
static lc_name() {
return "ChatPromptTemplate";
}
get lc_aliases(): Record<string, string> {
return {
promptMessages: "messages",
};
}
promptMessages: Array<BaseMessagePromptTemplate | BaseMessage>;
validateTemplate = true;
templateFormat: TemplateFormat = "f-string";
constructor(input: ChatPromptTemplateInput<RunInput, PartialVariableName>) {
super(input);
// If input is mustache and validateTemplate is not defined, set it to false
if (
input.templateFormat === "mustache" &&
input.validateTemplate === undefined
) {
this.validateTemplate = false;
}
Object.assign(this, input);
if (this.validateTemplate) {
const inputVariablesMessages = new Set<string>();
for (const promptMessage of this.promptMessages) {
// eslint-disable-next-line no-instanceof/no-instanceof
if (promptMessage instanceof BaseMessage) continue;
for (const inputVariable of promptMessage.inputVariables) {
inputVariablesMessages.add(inputVariable);
}
}
const totalInputVariables = this.inputVariables as string[];
const inputVariablesInstance = new Set(
this.partialVariables
? totalInputVariables.concat(Object.keys(this.partialVariables))
: totalInputVariables
);
const difference = new Set(
[...inputVariablesInstance].filter(
(x) => !inputVariablesMessages.has(x)
)
);
if (difference.size > 0) {
throw new Error(
`Input variables \`${[
...difference,
]}\` are not used in any of the prompt messages.`
);
}
const otherDifference = new Set(
[...inputVariablesMessages].filter(
(x) => !inputVariablesInstance.has(x)
)
);
if (otherDifference.size > 0) {
throw new Error(
`Input variables \`${[
...otherDifference,
]}\` are used in prompt messages but not in the prompt template.`
);
}
}
}
_getPromptType(): "chat" {
return "chat";
}
private async _parseImagePrompts(
message: BaseMessage,
inputValues: InputValues<
PartialVariableName | Extract<keyof RunInput, string>
>
): Promise<BaseMessage> {
if (typeof message.content === "string") {
return message;
}
const formattedMessageContent = await Promise.all(
message.content.map(async (item) => {
if (item.type !== "image_url") {
return item;
}
let imageUrl = "";
if (typeof item.image_url === "string") {
imageUrl = item.image_url;
} else {
imageUrl = item.image_url.url;
}
const promptTemplatePlaceholder = PromptTemplate.fromTemplate(
imageUrl,
{
templateFormat: this.templateFormat,
}
);
const formattedUrl = await promptTemplatePlaceholder.format(
inputValues
);
if (typeof item.image_url !== "string" && "url" in item.image_url) {
// eslint-disable-next-line no-param-reassign
item.image_url.url = formattedUrl;
} else {
// eslint-disable-next-line no-param-reassign
item.image_url = formattedUrl;
}
return item;
})
);
// eslint-disable-next-line no-param-reassign
message.content = formattedMessageContent;
return message;
}
async formatMessages(
values: TypedPromptInputValues<RunInput>
): Promise<BaseMessage[]> {
const allValues = await this.mergePartialAndUserVariables(values);
let resultMessages: BaseMessage[] = [];
for (const promptMessage of this.promptMessages) {
// eslint-disable-next-line no-instanceof/no-instanceof
if (promptMessage instanceof BaseMessage) {
resultMessages.push(
await this._parseImagePrompts(promptMessage, allValues)
);
} else {
const inputValues = promptMessage.inputVariables.reduce(
(acc, inputVariable) => {
if (
!(inputVariable in allValues) &&
!(isMessagesPlaceholder(promptMessage) && promptMessage.optional)
) {
throw new Error(
`Missing value for input variable \`${inputVariable.toString()}\``
);
}
acc[inputVariable] = allValues[inputVariable];
return acc;
},
{} as InputValues
);
const message = await promptMessage.formatMessages(inputValues);
resultMessages = resultMessages.concat(message);
}
}
return resultMessages;
}
async partial<NewPartialVariableName extends string>(
values: PartialValues<NewPartialVariableName>
) {
// This is implemented in a way it doesn't require making
// BaseMessagePromptTemplate aware of .partial()
const newInputVariables = this.inputVariables.filter(
(iv) => !(iv in values)
) as Exclude<Extract<keyof RunInput, string>, NewPartialVariableName>[];