node.js - UnhandledPromiseRejectionWarning:TypeError:_base64Stream2.default.encode 不是函数
问题描述
我正在尝试在本文的帮助下制作这个简单的 api。阅读本文的主要目的是学习 react native,但它从 nodejs 中的服务器开始。我无法使其正常运行。这是文章链接的链接
这是 server.js 文件的代码
import express from 'express';
import http from 'http';
import giphyapi from 'giphy-api';
import base64 from 'base64-stream';
// Initialize http server
const app = express();
// Register /gif endpoint that returns base64 encoded gif
app.get('/gif', async (req, res) => {
res.json({
gif: await fetchGif(),
});
});
// Launch the server on port 3000
const server = app.listen(3000, () => {
const { address, port } = server.address();
console.log(`Listening at http://${address}:${port}`);
});
// Fetch random GIF url with Giphy API, download and Base64 encode it
export const fetchGif = async () => {
const item = await giphyapi().random('cat');
return await encode(await download(item.data.image_url));
};
// File download helper
const download = async (url) => {
return new Promise((resolve, reject) => {
let req = http.get(url.replace('https', 'http'));
req.on('response', res => {
resolve(res);
});
req.on('error', err => {
reject(err);
});
});
};
// Base64 encode helper
const encode = async (content) => {
let output = 'data:image/gif;base64,';
const stream = content.pipe(base64.encode());
return new Promise((resolve, reject) => {
stream.on('readable', () => {
let read = stream.read();
if (read) {
output += read.toString();
}
else {
resolve(output);
}
});
stream.on('error', (err) => {
reject(err);
});
});
};
解决方案
出现该错误是因为第三方库“base64-stream”没有“encoded”功能,可能在以前的版本中存在。
要解决这个问题,您需要更改一些代码行,使您的服务器看起来像下面的代码。
const express = require('express'); // instead of "import express from 'express';"
const http = require('http'); // instead of "import http from 'http';"
const giphyapi = require('giphy-api'); // instead of "import http from 'http';"
const { Base64Encode } = require('base64-stream'); // instead of "import base64 from 'base64-stream';"
// Initialize http server
const app = express();
// Register /gif endpoint that returns base64 encoded gif
app.get('/gif', async (req, res) => {
try {
const gif = await fetchGif();
res.json({ gif });
} catch (error) {
res.status(500).send({ error });
}
});
// Base64 encode helper
const encode = (content) => {
let output = 'data:image/gif;base64,';
const stream = content.pipe(new Base64Encode()); // instead of "const stream = content.pipe(base64.encode());"
return new Promise((resolve, reject) => {
stream.on('readable', () => {
let read = stream.read();
if (read) {
output += read.toString();
}
else {
resolve(output);
}
});
stream.on('error', (err) => {
reject(err);
});
});
};
// Launch the server on port 3000
const server = app.listen(3000, () => {
const { address, port } = server.address();
console.log(`Listening at http://${address}:${port}`);
});
// Fetch random GIF url with Giphy API, download and Base64 encode it
const fetchGif = async () => {
try {
const item = await giphyapi().random('cat');
const image = await download(item.data.image_url);
return await encode(image);
} catch (error) {
console.log('fetchGif', error);
}
};
// File download helper
const download = (url) => {
return new Promise((resolve, reject) => {
let req = http.get(url.replace('https', 'http'));
req.on('response', res => {
resolve(res);
});
req.on('error', err => {
reject(err);
});
});
};