Saxon » SaxonJS

Two questions:

(a) could you please give the exact error message? You seem to suggest that it mentioned checksums, but you haven't told us exactly what it said.

(b) how did you convert the file containing the generated SEF to a string, in order to supply it as the stylesheet-text property? Did you apply any escaping, and if so how? My guess would be that in converting the SEF to a string you inadverently changed something that affected the checksum.

thanks for the quick response!

sorry but we are unable to determine how we managed to get the checksum error and correct it... will keep looking. the parsing error still persists.

so as a test case if our xslt is thus:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:eml="https://eml.ecoinformatics.org/eml-2.2.0"
    exclude-result-prefixes="xs"
    version="1.0">
    <xsl:output omit-xml-declaration="yes"/>
    <xsl:template match="/">"datasetName": "<xsl:value-of select="/eml:eml/dataset/title"/>"
    </xsl:template>
</xsl:stylesheet>

we convert to SEF using xslt3 thus:

npx xslt3 -xsl:transforms/sims_eml_transform.2.xsl -export:transforms/sims_eml_transform.2.sef.json -t -ns:##html5

copy the output from the sef directly into a string in node:

var saxonjs = require('saxon-js');

var sef = '{"N":"package","version":"10","packageVersion":"1","saxonVersion":"SaxonJS 2.4","target":"JS","targetVersion":"2","name":"TOP-LEVEL","relocatable":"false","buildDateTime":"2022-05-31T14:06:34.639-07:00","ns":"xml=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0","C":[{"N":"co","binds":"","id":"0","C":[{"N":"mode","onNo":"TC","flags":"","patternSlots":"0","prec":"","C":[{"N":"templateRule","rank":"0","prec":"0","seq":"0","ns":"xml=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0","minImp":"0","flags":"s","slots":"200","baseUri":"file:///home/ubuntu64/node/saxonjs/transforms/sims_eml_transform.2.xsl","line":"8","module":"sims_eml_transform.2.xsl","expand-text":"false","match":"/","prio":"-0.5","matches":"ND","C":[{"N":"p.nodeTest","role":"match","test":"ND","sType":"1ND","ns":"= xml=~ fn=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0 "},{"N":"sequence","role":"action","sType":"*NT ","C":[{"N":"valueOf","sType":"1NT ","C":[{"N":"str","sType":"1AS ","val":"\"datasetName\": \""}]},{"N":"valueOf","flags":"l","sType":"1NT ","C":[{"N":"fn","name":"string-join","role":"select","C":[{"N":"first","C":[{"N":"forEach","sType":"*AS ","C":[{"N":"data","sType":"*A ","C":[{"N":"mergeAdj","C":[{"N":"docOrder","sType":"*NE","role":"select","line":"2","C":[{"N":"docOrder","sType":"*NE","ns":"= xml=~ fn=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0 ","C":[{"N":"slash","op":"/","C":[{"N":"slash","op":"/","C":[{"N":"slash","op":"/","C":[{"N":"root"},{"N":"axis","name":"child","nodeTest":"*NE nQ{https://eml.ecoinformatics.org/eml-2.2.0}eml"}]},{"N":"axis","name":"child","nodeTest":"*NE u[NE nQ{}dataset,NE nQ{http://www.w3.org/1999/xhtml}dataset]"}]},{"N":"axis","name":"child","nodeTest":"*NE u[NE nQ{}title,NE nQ{http://www.w3.org/1999/xhtml}title]"}]}]}]}]}]},{"N":"fn","name":"string","sType":"1AS ","C":[{"N":"dot"}]}]}]},{"N":"str","sType":"1AS ","val":" "}]}]},{"N":"valueOf","sType":"1NT ","C":[{"N":"str","sType":"1AS ","val":"\"\n    "}]}]}]}]}]},{"N":"overridden"},{"N":"output","C":[{"N":"property","name":"Q{http://saxon.sf.net/}stylesheet-version","value":"10"},{"N":"property","name":"omit-xml-declaration","value":"yes"}]},{"N":"decimalFormat"}],"Σ":"b434ef2d"}';

saxonjs.transform({
  stylesheetText: sef,
  sourceFileName: "transforms/generated_eml.xml",
  destination: "serialized",
  logLevel: 10
}, "async")
.then (output => {
  console.log(output.principalResult);
});

the error:

ubuntu64@DeepThought:~/node/saxonjs$ node test.js

/home/ubuntu64/node/saxonjs/node_modules/saxon-js/SaxonJS2N.js:4840 A;ob.fb("Transform with options: "+G(z),2);try{var B=r(z);B.Ca&&(B.outputProperties=k(B.Ca))}catch(O){if(A)throw O;return Promise.reject(O)}var R=Z.baseURL();if(B.Jb)var J=B.Jb=F(B.Jb);else B.fc&&(J=B.fc=F(B.fc));B.Vf=J||B.Vf;if(B.Wc)var fa=B.Wc=F(B.Wc);else B.Vc&&(fa=B.Vc=F(B.Vc));B.Zd=fa||B.Zd;"function"===typeof Z.deliverMessage&&Z.deliverMessage(z);"number"===typeof B.If&&ob.setLogLevel(B.If);if(A)return t(B);B.Xh=!0;z=[];var ka=B.stylesheetInternal||null;if(!ka)if(J=B.stylesheetText)try{ka=JSON.parse(J)}catch(O){throw new L("Error parsing supplied SEF", ^ Error at new L (/home/ubuntu64/node/saxonjs/node_modules/saxon-js/SaxonJS2N.js:3944:463) at Object.transform (/home/ubuntu64/node/saxonjs/node_modules/saxon-js/SaxonJS2N.js:4840:530) at Object. (/home/ubuntu64/node/saxonjs/test.js:8:9) at Module._compile (node:internal/modules/cjs/loader:1103:14) at Object.Module._extensions..js (node:internal/modules/cjs/loader:1155:10) at Module.load (node:internal/modules/cjs/loader:981:32) at Function.Module._load (node:internal/modules/cjs/loader:822:12) at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:77:12) at node:internal/main/run_main_module:17:47 { message: 'Error parsing supplied SEF', name: 'XError', code: 'SXJS0006' }

hope this provides sufficient detail.

thanks again!

but this works fine (object instead of string):

var saxonjs = require('saxon-js');

var sef = {"N":"package","version":"10","packageVersion":"1","saxonVersion":"SaxonJS 2.4","target":"JS","targetVersion":"2","name":"TOP-LEVEL","relocatable":"false","buildDateTime":"2022-05-31T14:06:34.639-07:00","ns":"xml=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0","C":[{"N":"co","binds":"","id":"0","C":[{"N":"mode","onNo":"TC","flags":"","patternSlots":"0","prec":"","C":[{"N":"templateRule","rank":"0","prec":"0","seq":"0","ns":"xml=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0","minImp":"0","flags":"s","slots":"200","baseUri":"file:///home/ubuntu64/node/saxonjs/transforms/sims_eml_transform.2.xsl","line":"8","module":"sims_eml_transform.2.xsl","expand-text":"false","match":"/","prio":"-0.5","matches":"ND","C":[{"N":"p.nodeTest","role":"match","test":"ND","sType":"1ND","ns":"= xml=~ fn=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0 "},{"N":"sequence","role":"action","sType":"*NT ","C":[{"N":"valueOf","sType":"1NT ","C":[{"N":"str","sType":"1AS ","val":"\"datasetName\": \""}]},{"N":"valueOf","flags":"l","sType":"1NT ","C":[{"N":"fn","name":"string-join","role":"select","C":[{"N":"first","C":[{"N":"forEach","sType":"*AS ","C":[{"N":"data","sType":"*A ","C":[{"N":"mergeAdj","C":[{"N":"docOrder","sType":"*NE","role":"select","line":"2","C":[{"N":"docOrder","sType":"*NE","ns":"= xml=~ fn=~ xsl=~ xs=~ eml=https://eml.ecoinformatics.org/eml-2.2.0 ","C":[{"N":"slash","op":"/","C":[{"N":"slash","op":"/","C":[{"N":"slash","op":"/","C":[{"N":"root"},{"N":"axis","name":"child","nodeTest":"*NE nQ{https://eml.ecoinformatics.org/eml-2.2.0}eml"}]},{"N":"axis","name":"child","nodeTest":"*NE u[NE nQ{}dataset,NE nQ{http://www.w3.org/1999/xhtml}dataset]"}]},{"N":"axis","name":"child","nodeTest":"*NE u[NE nQ{}title,NE nQ{http://www.w3.org/1999/xhtml}title]"}]}]}]}]}]},{"N":"fn","name":"string","sType":"1AS ","C":[{"N":"dot"}]}]}]},{"N":"str","sType":"1AS ","val":" "}]}]},{"N":"valueOf","sType":"1NT ","C":[{"N":"str","sType":"1AS ","val":"\"\n    "}]}]}]}]}]},{"N":"overridden"},{"N":"output","C":[{"N":"property","name":"Q{http://saxon.sf.net/}stylesheet-version","value":"10"},{"N":"property","name":"omit-xml-declaration","value":"yes"}]},{"N":"decimalFormat"}],"Σ":"b434ef2d"};

saxonjs.transform({
  stylesheetInternal: sef,
  sourceFileName: "transforms/generated_eml.xml",
  destination: "serialized",
  logLevel: 10
}, "async")
.then (output => {
  console.log(output.principalResult);
});

I think you need to make sure you read in the file from the file system with e.g.

const SaxonJS = require('saxon-js');
const fs = require('fs');

const sef = fs.readFileSync('sheet.sef.json', 'utf8');

SaxonJS.transform({
  stylesheetText: sef,
  sourceFileName: "sample1.xml",
  destination: "serialized",
  logLevel: 10
}, "async")
.then (output => {
  console.log(output.principalResult);
});

If you copy/paste the JSON from an editor into a JavaScript string literal delimited by quotes you basically have, in the case of the code containing an escaped \", some string that lacks the proper escaping, you would probably need to double backslashes or at least do some doube escaping due to the use of JSON inside of a JavaScript string literal.

As Martin has commented, the problem is the escaping of \" (in particular at "val":"\"datasetName\": \"" in your SEF). So simply copying the SEF JSON and pasting into a string will not work.

As you've noted, you can instead use stylesheetInternal with the SEF JSON directly. Alternatively, to use stylesheetText you would need to call JSON.stringify() on the SEF JSON object to produce a suitable string with the right escaping.

Otherwise, indeed reading the SEF from a file resource (e.g. using fs.readFileSync) produces a string with the correct escaping that can be supplied to stylesheetText.

(Note that internally, SaxonJS is doing JSON.parse() on the string supplied for stylesheetText.)

Just in case you're going through the same hoops as I was to understand this: there's a text node in the stylesheet whose value is

"datasetName" : "

and to put this in JSON it has to be escaped as

"val":"\"datasetName\": \""

and to put that JSON into a Javascript string, all the quotes and backslashes have to be escaped again so it becomes

\"val\":\"\\\"datasetName\\\": \\\"\"

The alternative would be to use a "raw string" with backtick notation.

thanks so much for all of these great responses!

yes, thats a bunch of escaping!! i believe we've decided to change our approach and access the SEF data via file system or URI and avoid some of that complexity.

thanks again!