如何在使用 gridfs 保存之前调整大小和图像?
How to resize and image before saving it with gridfs?
我是 mongoDB 和 gridfs 的初学者。我有一个代码可以在数据库中保存传入的图像。但我想在保存之前调整图像大小。试过用sharp,但是不太懂怎么用
我尝试了以下代码,但它不起作用
const storage = new GridFsStorage({
url: mongoURI,
file: (req, file) => {
return new Promise((resolve, reject) => {
const filename = req.params.userID;
const fileInfo = {
filename: filename,
bucketName: "ProfilePic",
};
resolve(fileInfo);
});
}
});
const upload = multer({ storage });
router.post("/setProfilePic/:userID", upload.single("picture"), async(req, res) => {
//code not working
await sharp(req.file.path)
.resize(500)
.jpeg({quality: 50})
.toFile(
path.resolve(req.file.destination,'resized',image)
)
// end of non working code
return res.status(200).json({state: "ok"})
});
我的解决方案是使用 'multer-gridfs-storage'
中的 fromStream
方法
想法是这样的:
- 使用
multer
解析文件,得到文件缓冲区(原始数据)
- 使用
sharp
捕获输入缓冲区并创建另一个包含调整大小的图像的缓冲区。
- 使用
Readable
创建可读流,然后应用 fromStream
方法将流传输到数据库。
实施
const multer = require('multer')
const { GridFsStorage } = require("multer-gridfs-storage");
const { Readable } = require("stream"); // from nodejs
const sharp = require("sharp");
const storage = new GridFsStorage({
url: mongoURI,
options: { useUnifiedTopology: true }, // silence the warning
file: () => ({ bucketName: "ProfilePic",filename: req.params.userID }),
});
router.post("/setProfilePic/:userID",multer().single('picture'),(req,res) => {
const file = req.file
const buffer = file.buffer
// chain sharp methods
sharp(buffer)
.resize(500)
.jpeg({ quality: 50 })
.toBuffer((err, data, info) => {
// data here directly contains the buffer object.
const fileStream = Readable.from(data);
// write the resized stream to the database.
storage.fromStream(fileStream, req, file).then(() => {
res.json({ state: 'ok' });
});
});
})
我没有充分利用 multer 的存储引擎,而是创建了自己的流。
我也是一个 MongoDB 初学者,所以我很高兴能够成功。如果还是不行,请留言,我会尽力解决。
我用的是之前的答案。我做了一些更改以使其工作。我的 req.file.buffer 始终未定义。所以我做了一些改动。
我想在下面强调两件事
确保你使用的是多版本“^2.0.0-rc.1”。
您可以通过
创建缓冲区
const buffer = await getStream.buffer(req.file.stream);
其余解决方案完全相同。这是完整的代码示例。
const multer = require('multer')
const { GridFsStorage } = require("multer-gridfs-storage");
const { Readable } = require("stream"); // from nodejs
const sharp = require("sharp");
const getStream = require("get-stream");
const storage = new GridFsStorage({
url: mongoURI,
options: { useUnifiedTopology: true }, // silence the warning
file: () => ({ bucketName: "ProfilePic",filename: req.params.userID }),
});
app.post("/setProfilePic/:userID", multer.single("image"), async (req, res) => {
const file = req.file;
const buffer = await getStream.buffer(req.file.stream);
// chain sharp methods
sharp(buffer)
.resize(200, 100)
.jpeg({ quality: 50 })
.toBuffer((err, data, info) => {
// data here directly contains the buffer object.
const fileStream = Readable.from(data);
// write the resized stream to the database.
storage.fromStream(fileStream, req, file).then(() => {
res.json({ state: "ok" });
});
});
});
我是 mongoDB 和 gridfs 的初学者。我有一个代码可以在数据库中保存传入的图像。但我想在保存之前调整图像大小。试过用sharp,但是不太懂怎么用
我尝试了以下代码,但它不起作用
const storage = new GridFsStorage({
url: mongoURI,
file: (req, file) => {
return new Promise((resolve, reject) => {
const filename = req.params.userID;
const fileInfo = {
filename: filename,
bucketName: "ProfilePic",
};
resolve(fileInfo);
});
}
});
const upload = multer({ storage });
router.post("/setProfilePic/:userID", upload.single("picture"), async(req, res) => {
//code not working
await sharp(req.file.path)
.resize(500)
.jpeg({quality: 50})
.toFile(
path.resolve(req.file.destination,'resized',image)
)
// end of non working code
return res.status(200).json({state: "ok"})
});
我的解决方案是使用 'multer-gridfs-storage'
fromStream
方法
想法是这样的:
- 使用
multer
解析文件,得到文件缓冲区(原始数据) - 使用
sharp
捕获输入缓冲区并创建另一个包含调整大小的图像的缓冲区。 - 使用
Readable
创建可读流,然后应用fromStream
方法将流传输到数据库。
实施
const multer = require('multer')
const { GridFsStorage } = require("multer-gridfs-storage");
const { Readable } = require("stream"); // from nodejs
const sharp = require("sharp");
const storage = new GridFsStorage({
url: mongoURI,
options: { useUnifiedTopology: true }, // silence the warning
file: () => ({ bucketName: "ProfilePic",filename: req.params.userID }),
});
router.post("/setProfilePic/:userID",multer().single('picture'),(req,res) => {
const file = req.file
const buffer = file.buffer
// chain sharp methods
sharp(buffer)
.resize(500)
.jpeg({ quality: 50 })
.toBuffer((err, data, info) => {
// data here directly contains the buffer object.
const fileStream = Readable.from(data);
// write the resized stream to the database.
storage.fromStream(fileStream, req, file).then(() => {
res.json({ state: 'ok' });
});
});
})
我没有充分利用 multer 的存储引擎,而是创建了自己的流。
我也是一个 MongoDB 初学者,所以我很高兴能够成功。如果还是不行,请留言,我会尽力解决。
我用的是之前的答案。我做了一些更改以使其工作。我的 req.file.buffer 始终未定义。所以我做了一些改动。
我想在下面强调两件事
确保你使用的是多版本“^2.0.0-rc.1”。
您可以通过
创建缓冲区
const buffer = await getStream.buffer(req.file.stream);
其余解决方案完全相同。这是完整的代码示例。
const multer = require('multer')
const { GridFsStorage } = require("multer-gridfs-storage");
const { Readable } = require("stream"); // from nodejs
const sharp = require("sharp");
const getStream = require("get-stream");
const storage = new GridFsStorage({
url: mongoURI,
options: { useUnifiedTopology: true }, // silence the warning
file: () => ({ bucketName: "ProfilePic",filename: req.params.userID }),
});
app.post("/setProfilePic/:userID", multer.single("image"), async (req, res) => {
const file = req.file;
const buffer = await getStream.buffer(req.file.stream);
// chain sharp methods
sharp(buffer)
.resize(200, 100)
.jpeg({ quality: 50 })
.toBuffer((err, data, info) => {
// data here directly contains the buffer object.
const fileStream = Readable.from(data);
// write the resized stream to the database.
storage.fromStream(fileStream, req, file).then(() => {
res.json({ state: "ok" });
});
});
});