newCashBook/epub_node/router/epub/image.js

import { dirExists } from "#utils";
import { files_insert } from "#db";
import crypto from "crypto";
import fs from "node:fs";

export async function saveImgs( epub ) {
  // const res = await Promise.allSettled(imgs.map(elm => {
  // }))
  let imgs = epub.listImage();
  console.log(imgs[0]);
  console.log(1121, imgs.length);
  await epub.getImageAsync(imgs[2].id).then(async function ( [data,mimeType] ) {
    console.log(`\ngetImage: cover\n`);
    console.log(data);
    const img_md5 = await calculateMD5FromBuffer(data);
    console.log(img_md5);
    console.log(mimeType);
    console.log(1616,formatSize(data.length));
    const params = {
      file_id: img_md5,
      md5: img_md5,
      mimetype: mimeType,
      size: data.length,
      name: imgs[0].id,
      path: imgs[0].href,
    }

    const uploadPath = "./base_files/" + img_md5;
    dirExists("./base_files/");

    // 如果需要将 JSON 保存为文件，可以使用 fs.writeFile()
    fs.writeFile(uploadPath,data,( err ) => {
      if ( err ) {
        console.error("Error writing JSON file:",err);
      } else {
        console.log("JSON data saved to output.json");
      }
    });

    await files_insert(params)
  });
}

function calculateMD5( filePath ) {
  const hash = crypto.createHash("md5");
  const stream = fs.createReadStream(filePath);

  stream.on("data",( chunk ) => {
    hash.update(chunk);
  });

  stream.on("end",() => {
    console.log("MD5 hash:",hash.digest("hex"));
  });
}

export async function calculateMD5FromStream( fileStream ) {
  return new Promise(( resolve,reject ) => {
    const hash = crypto.createHash("md5");

    // 错误处理
    fileStream.on("error",( err ) => {
      console.error("Error reading file stream:",err);
      reject("生成失败!"); // 使用 reject 传递错误信息
    });

    // 监听 'data' 事件，更新 MD5 哈希
    fileStream.on("data",( chunk ) => {
      hash.update(chunk);
    });

    // 监听 'end' 事件，文件读取完毕后输出 MD5 值
    fileStream.on("end",() => {
      const md5 = hash.digest("hex");
      console.log("MD5 Hash:",md5);
      resolve(md5); // 正常计算完 MD5 后 resolve
    });
  });
}

export function calculateMD5FromBuffer( buffer ) {
  return new Promise(( resolve,reject ) => {
    try {
      // 使用 crypto 计算 MD5
      const hash = crypto.createHash("md5");
      hash.update(buffer); // 直接更新 hash

      const md5 = hash.digest("hex"); // 获取最终的 MD5 值
      console.log("MD5 Hash:",md5);
      resolve(md5); // 返回 MD5
    } catch ( err ) {
      console.error("Error calculating MD5:",err);
      reject("生成失败!");
    }
  });
}

const formatSize = ( bytes ) => {
  if ( bytes < 1024 ) return `${ bytes } 字节`;
  else if ( bytes < 1024 * 1024 ) return `${ ( bytes / 1024 ).toFixed(2) } KB`;
  else if ( bytes < 1024 * 1024 * 1024 )
    return `${ ( bytes / ( 1024 * 1024 ) ).toFixed(2) } MB`;
  else return `${ ( bytes / ( 1024 * 1024 * 1024 ) ).toFixed(2) } GB`;
};