How to watermark on sever?

[seyedasfar]

My client-side uploading photos to sever and saving on Gridfs MongoDB, How can I able to watermark before storing my images on database?

what I tried.

      const storeUpload = async (file) => {
        watermark([file, 'https://dcassetcdn.com/design_img/1559024/551167/551167_7840631_1559024_911ff84c_image.png'])
          .image(watermark.image.lowerRight(0.5))
          .then(img => file = img);
        
        const { createReadStream, filename } = await file
        const stream = createReadStream()
        await new Promise((resolve, reject) =>
          stream
            .pipe(bucket.openUploadStream(filename))
            .on('error', error => reject(error))
            .on('finish', (res) => {
              resolve()
              photos.push(res._id)
            })
        )
      }

      await Promise.all(data.photos.map(file => storeUpload(file)))

[skliffmueller]

watermarkjs was built with the intent to only run on client side as it relies on the HTMLCanvasContext elements to exist which is only native to browsers. Typically you'd watermark on client side then upload the watermarked image to the server.

You might be able to do some hackery, or fork and update watermarkjs to use something like this https://github.com/Automattic/node-canvas to give node js canvas abilities.

The traditional way is to use something like graphicmagick gm Here is some articles on how to do that
http://www.proccli.com/2013/10/watermark-images-with-node.js-and-graphicsmagick
https://stackoverflow.com/questions/24375090/node-js-express-and-gm-graphicsmagick-adding-watermarks-and-general-image
aheckmann/gm#276

Note: You must install graphicsmagick library on your system, or the server itself. Here are some Dockerfiles which show some of the resources you will have to install via aptitude, or apk
https://hub.docker.com/r/jameskyburz/graphicsmagick-alpine/dockerfile
https://github.com/jtblin/debian-node-graphicsmagick/blob/master/Dockerfile

And a general guide to installation:
http://www.graphicsmagick.org/README.html