I'm working on generating an Excel file (e.g., using libraries like ExcelJS or similar) where I need to display a logo image. The image is fetched from a server and converted to a base64 string.

Here's the code I'm using to fetch and convert the image:

const axios = require('axios');

async function convertImageToBase64(imageUrl) {
    try {
        const response = await axios.get(imageUrl, { responseType: 'arraybuffer' });
        const base64Image = Buffer.from(response.data, 'binary').toString('base64');
        const contentType = response.headers['content-type'];
        return `data:${contentType};base64,${base64Image}`;
    } catch (e) {
        console.error(`Error while converting image to base64: ${e.message}`, e.stack);
        throw new Error('Error while converting image to base64: ' + e);
    }
}

I successfully got a base64 string like:
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAA...

My question is: How can I display this base64 image in a generated Excel file?

I'm not sure how to properly embed or display the image using the base64 string.

Thanks in advance!

The link to the documentation
https://jsreport.net/learn/xlsx

A demo with you case
https://playground.jsreport.net/w/anon/LyTAxE8t

async function convertImageToBase64(imageUrl) {
try {
const response = await axios.get(imageUrl, { responseType: 'arraybuffer' });
const base64Image = Buffer.from(response.data, 'binary').toString('base64');
console.log('returning base64')
return base64Image;
} catch (e) {
console.error(Error while converting image to base64: ${e.message}, e.stack);
throw new Error('Error while converting image to base64: ' + e);
}
}

I successfully get the base64 string, and then I try to inject it into an Excel template using this syntax:

{{#xlsxAddImage "test" "sheet1.xml" 0 0 10 30}}
{{myDataURIForImage}}
{{/xlsxAddImage}}

However, I'm encountering the following error during template rendering:

Error: "xlsxAddImage" helper call failed
(because) cannot read properties of undefined (reading '[Content_Types].xml')
at module.exports (/app/node_modules/@jsreport/jsreport-core/lib/shared/createError.js:10:13)
at WorkerReporter.createError (/app/node_modules/@jsreport/jsreport-core/lib/shared/reporter.js:53:12)
at getEnhancedHelperError (/app/node_modules/@jsreport/jsreport-core/lib/worker/render/executeEngine.js:425:54)
at /app/node_modules/@jsreport/jsreport-core/lib/worker/render/executeEngine.js:443:15
wrapped by:
Error: Error while executing xlsx recipe
(because) "xlsxAddImage" helper call failed
(because) cannot read properties of undefined (reading '[Content_Types].xml')
(system-helpers.js line 3535:41)
3533 | const name = imageName + '.png'
3534 |

3535 | if (!options.data.root.$xlsxTemplate['[Content_Types].xml'].Types.Default.filter(function (t) { return t.$.Extension === 'png' }).length) {
| ^
3536 | options.data.root.$xlsxTemplate['[Content_Types].xml'].Types.Default.push({
3537 | $: {
3538 | Extension: 'png',
(system-helpers.js line 3655:17)
3653 | }
3654 |
3655 | return fn.apply(this, arguments)
| ^
3656 | }
3657 | }
3658 |
(system-helpers.js line 3685:30)
3683 | }
3684 | function xlsxAddImage (...args) {
3685 | return __xlsx.xlsxAddImage.call(this, ...args)
| ^
3686 | }
3687 |
3688 | function xlsxAddSheet (...args) {
| ^
2952 | },
2953 | m: function (options) {
2954 | return mergeOrFormulaCell.call(this, 'mergeCell', options)
(system-helpers.js line 2983:31)
2981 | try {
2982 | if (values.length > 0) {
2983 | return targetHelper.call(context, ...values, options)
| ^
2984 | }
2985 |
2986 | return targetHelper.call(context, options)
(system-helpers.js line 3015:18)
3013 | __xlsxD.assertDataArg(type != null, '_D helper t arg is required')
3014 |
3015 | return __xlsxD.resolveHelper(type, arguments.length, this, values, optionsToUse)
| ^
3016 | }
3017 |
3018 | // alias for {{_D t='r'}} helper call, we do it this way to optimize size of the generated xml
(system-helpers.js line 3080:13)
3078 | }
3079 |
3080 | return _D.call(this, data, options)
| ^
3081 | }
3082 |
3083 | // alias for {{_D t='c'}} helper with autodetect call with calcChainUpdate: true

And one more thing: Can the logo be printed directly as base64 in the Excel template? I need to print the logo multiple times and also do it dynamically.