Add precheck pdf before return to Client

[Ngô Duy]

Hello i create a server to generate PDF
const jsreport = require('jsreport')()

But sometime PDF generate with error fonts (I try to find problem but still dont know why). So I use pdf-parse to validate if fonts error. But i use it from client. The problem is I have more than 1 client so i want use pdf-parse from server before send PDF to client.

Is there any way to do that ?

[jan_blaha]

The best solution is mostly to a custom script and afterRender hook for the post-processing
https://jsreport.net/learn/scripts

Or you can do it also in general, but this will be invoked quite at the end of the pipeline.

const jsreport = require('jsreport')()
jsreport.afterRenderListeners.add('someName', async (req, res) => {
    console.log(res.content)
})

btw, the issue is random right? How do you find out there is an issue in fonts with pdf-parse?

[Ngô Duy]

yes it happens randomly but not because of pdf-parse but i use pdf-parse to read the text in pdf to confirm that there is no font error i will return it to client and if font error i will output the pdf again As long as there is no font error, that's it.

[QUESTION]
jsreport.afterRenderListeners.add('someName', async (req, res) => {
console.log(res.content)
})
how can i use check pdf-parse in this. and when successful, I return the client and if not successful I will generate the PDF again?

[jan_blaha]

[QUESTION]
jsreport.afterRenderListeners.add('someName', async (req, res) => {
console.log(res.content)
})

hm, after trying it out, there are too many problems with this solution.

The custom script could work like this

async function afterRender (req, res) {    
    // here use extra code to check if res.content is valid
    if (Math.random() > 0.5) {
        // its ok
        return
    }

    //retry
    const retryRes = await require('jsreport-proxy').render({...req})
    res.content = retryRes.content
}

The last option is to use an extra service as middleware that will do the validation and retry.

[Ngô Duy]

Hello.

jsreport.afterRenderListeners.add('someName', async (req, res) => {
    console.log("TEST")
    afterRender(req,res)
})
async function afterRender (req, res) {    
    console.log(res.content)
}

i push a line console.log("TEST") in this function and it's show 4 times when i generate a report. What happen ? (I use some background, footer, header,... )

I try

const jsreport = require('jsreport')()

jsreport.afterRenderListeners.add('someName', async (req, res) => {
    console.log("HAHAHA")
    afterRender(req,res)
})
async function afterRender (req, res) {    
    // here use extra code to check if res.content is valid
    if (Math.random() > 0.5) {
        // its ok
        return
    }

    //retry
    const retryRes = await require('jsreport-proxy').render({...req})
    res.content = retryRes.content
}
if (process.env.JSREPORT_CLI) {
  // export jsreport instance to make it possible to use jsreport-cli
  module.exports = jsreport
} else {
  jsreport.init().then(() => {
	console.log("JSreport POWERFUL!")
    // running
  }).catch((e) => {
    // error during startup
    console.error(e.stack)
    process.exit(1)
  })
}

But it told me that: "Can not find jsreport-proxy module" ?

Where is the list event listenner i can use ? Example: afterRenderListeners ?

Can i throw error to client if i detect error font ?

[jan_blaha]

But it told me that: "Can not find jsreport-proxy module" ?

The code I shared should be placed in the custom script entity
https://jsreport.net/learn/scripts