sparkline.ts•8.35 kB
import { Tool, McpError, ErrorCode } from "@modelcontextprotocol/sdk/types.js";
import axios from "axios";
import * as fs from "fs";
import * as path from "path";
import { getDownloadPath } from "../utils/file.js";
import { QuickChartUrls } from "../utils/config.js";
/**
* Tool description
*/
export const CREATE_SPARKLINE_USING_CHARTJS_TOOL: Tool = {
name: "create-sparkline-using-chartjs",
description:
"Create sparkline charts using Chart.js - get sparkline image URL or save sparkline image to file",
inputSchema: {
type: "object",
properties: {
action: {
type: "string",
enum: ["get_url", "save_file"],
description: "Whether to get sparkline URL or save as file",
},
outputPath: {
type: "string",
description:
"Path where to save the file (only used with action=save_file)",
},
chart: {
type: "object",
description: "Chart.js configuration for sparkline",
},
width: {
type: "integer",
description: "Chart width in pixels (default: 100)",
},
height: {
type: "integer",
description: "Chart height in pixels (default: 30)",
},
devicePixelRatio: {
type: "integer",
enum: [1, 2],
description: "Device pixel ratio (default: 2)",
},
backgroundColor: {
type: "string",
description: "Background color (default: transparent)",
},
},
required: ["action", "chart"],
},
};
/**
* Validates
*/
function validateChart(chart: any): void {
if (!chart || typeof chart !== "object") {
throw new McpError(
ErrorCode.InvalidParams,
"Chart configuration is required and must be an object"
);
}
}
function validateAction(action: string): void {
if (!action || typeof action !== "string" || action.trim().length === 0) {
throw new McpError(
ErrorCode.InvalidParams,
"Action must be a non-empty string"
);
}
const validActions = ["get_url", "save_file"];
if (!validActions.includes(action)) {
throw new McpError(
ErrorCode.InvalidParams,
`Invalid action: ${action}. Valid actions are: ${validActions.join(", ")}`
);
}
}
function validateOutputPath(
outputPath: string | undefined,
action: string
): void {
if (
action === "save_file" &&
(!outputPath ||
typeof outputPath !== "string" ||
outputPath.trim().length === 0)
) {
throw new McpError(
ErrorCode.InvalidParams,
"Output path is required for save_file action"
);
}
}
function validateDimensions(width?: number, height?: number): void {
if (width !== undefined) {
if (!Number.isInteger(width) || width <= 0 || width > 10000) {
throw new McpError(
ErrorCode.InvalidParams,
"Width must be a positive integer between 1 and 10000"
);
}
}
if (height !== undefined) {
if (!Number.isInteger(height) || height <= 0 || height > 10000) {
throw new McpError(
ErrorCode.InvalidParams,
"Height must be a positive integer between 1 and 10000"
);
}
}
}
function validateDevicePixelRatio(devicePixelRatio?: number): void {
if (devicePixelRatio !== undefined) {
const validRatios = [1, 2];
if (!validRatios.includes(devicePixelRatio)) {
throw new McpError(
ErrorCode.InvalidParams,
`Invalid device pixel ratio: ${devicePixelRatio}. Valid ratios are: ${validRatios.join(", ")}`
);
}
}
}
function validateBackgroundColor(backgroundColor?: string): void {
if (backgroundColor !== undefined) {
if (typeof backgroundColor !== "string" || backgroundColor.trim().length === 0) {
throw new McpError(
ErrorCode.InvalidParams,
"Background color must be a non-empty string"
);
}
}
}
/**
* Fetches
*/
function buildSparklineParams(
chart: any,
options: {
width?: number;
height?: number;
devicePixelRatio?: number;
backgroundColor?: string;
} = {}
): Record<string, string> {
const params: Record<string, string> = {
c: JSON.stringify(chart),
w: (options.width || 100).toString(),
h: (options.height || 30).toString(),
};
if (options.devicePixelRatio !== undefined) {
params.devicePixelRatio = options.devicePixelRatio.toString();
}
if (options.backgroundColor) {
params.bkg = options.backgroundColor;
}
return params;
}
function buildSparklineUrl(chart: any): string {
const encodedChart = encodeURIComponent(JSON.stringify(chart));
return `${QuickChartUrls.sparkline()}?c=${encodedChart}`;
}
async function fetchSparklineContent(
params: Record<string, string>,
format: string = "png"
): Promise<any> {
const queryString = new URLSearchParams(params).toString();
const sparklineUrl = `${QuickChartUrls.sparkline()}?${queryString}`;
const axiosConfig = {
responseType: "arraybuffer" as any,
timeout: 30000,
headers: {
"User-Agent":
"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
Accept: "image/*,*/*",
"Accept-Language": "en-US,en;q=0.9",
"Accept-Encoding": "gzip, deflate, br",
Connection: "keep-alive",
},
validateStatus: (status: number) => status >= 200 && status < 300,
};
try {
const response = await axios.get(sparklineUrl, axiosConfig);
return response.data;
} catch (error) {
const axiosError = error as any;
const message = axiosError.response
? `Failed to fetch sparkline content from QuickChart - Status: ${axiosError.response.status}`
: `Failed to fetch sparkline content from QuickChart - ${axiosError.message}`;
throw new McpError(ErrorCode.InternalError, message);
}
}
/**
* Tool handler
*/
export async function handleSparklineTool(args: any): Promise<any> {
const chart = args.chart as any;
const action = args.action as string;
validateChart(chart);
validateAction(action);
validateOutputPath(args.outputPath, action);
validateDimensions(args.width, args.height);
validateDevicePixelRatio(args.devicePixelRatio);
validateBackgroundColor(args.backgroundColor);
const params = buildSparklineParams(chart, {
width: args.width as number,
height: args.height as number,
devicePixelRatio: args.devicePixelRatio as number,
backgroundColor: args.backgroundColor as string,
});
const chartUrl = buildSparklineUrl(chart);
const result: any = {
content: [
{
type: "text",
text: "Below is the chart URL:",
},
{
type: "text",
text: chartUrl,
},
],
metadata: {
chartType: chart?.type || "sparkline",
generatedAt: new Date().toISOString(),
chartUrl: chartUrl,
},
};
try {
const pngData = await fetchSparklineContent(params, "png");
const pngBase64 = Buffer.from(pngData).toString("base64");
result.content.push(
{
type: "text",
text: "Below is the PNG image:",
},
{
type: "image",
data: pngBase64,
mimeType: "image/png",
}
);
result.metadata.pngBase64 = pngBase64;
} catch (error) {
result.content.unshift({
type: "text",
text: "⚠️ Failed to fetch chart image",
});
result.content.push({
type: "text",
text: `Error: ${error instanceof Error ? error.message : String(error)}`,
});
result.metadata.error =
error instanceof Error ? error.message : String(error);
}
if (action === "get_url") {
return result;
}
const format = "png";
const outputPath = getDownloadPath(
args.outputPath as string | undefined,
format
);
try {
const dir = path.dirname(outputPath);
if (!fs.existsSync(dir)) {
fs.mkdirSync(dir, { recursive: true });
}
const data = await fetchSparklineContent(params, format);
fs.writeFileSync(outputPath, data);
result.metadata.savedPath = outputPath;
result.content.push({
type: "text",
text: "Below is the saved file path:",
});
result.content.push({
type: "text",
text: outputPath,
});
return result;
} catch (error) {
throw new McpError(
ErrorCode.InternalError,
`Failed to save chart: ${
error instanceof Error ? error.message : String(error)
}`
);
}
}