I am not knowledgeable in nodejs or express, I have an API running on http://localhost:3000 and one of the endpoints call a function that uses file system to read file synchronously. When I make a post request on postman, it says in the console that it can’t read a path that doesn’t exist (which does to my understanding).
Relevant code:
index.js
app.post('/write',(req,res)=> { var body = req.body; console.log('endpoint reached'); console.log(body); logic.append(body.key,body.path); res.send('Writting to state was successful'); });
stateLogic.js (this occurs on first initialization of trieRoot)
async append(key,path) { var trieRoot = Buffer.from(programData.volatile.modularVariables.readSync(programData.persistent.paths.srcRoot,programData.volatile.modularVariables.encoding.utf8),'hex'); console.log(trieRoot); var db = programData.persistent.states.singularity; var trie = new merkle_patricia_tree_1.SecureTrie(db,trieRoot); var data = programData.volatile.modularVariables.readSync(path,programData.volatile.modularVariables.encoding.utf8); var format = programData.volatile.modularVariables.getFormat(path); var name = programData.volatile.modularVariables.getName(path); var inData = JSON.stringify({name,format,data}); console.log(`key: ${key} value: ${inData}`); await trie.put(Buffer.from(key),Buffer.from(inData)); var root = await trie.root; programData.volatile.modularVariables.write(programData.persistent.paths.srcRoot,root.toString('hex'),programData.volatile.modularVariables.writeCB); var retGet = await trie.get(Buffer.from(key)); console.log('Get returned:'+retGet.toString()); console.log(`From Stack: ${root.toString('hex')} From File: ${this.malleableVar}`); return; };
readSync function used:
readSync: (file,encoding)=>{return fs.readFileSync(file,{encoding:encoding,flag:'r'})},
srcRoot value used:
srcRoot: './storage/root.txt'
Console Error:
(node:18808) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, open './storage/root.txt'
Questions:
Why does it say the path doesn’t exist when it does? And what is it I am doing wrong? Thank you for your time.
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Answer
You’ve to use absolute path
instead of relative path
Modify your index.js
with the below code:
const path = require('path') // <-- import path module to use absolute path. app.post('/write',(req,res)=> { var body = req.body; const absPath = path.join(__dirname, body.path); // <-- absolute path console.log("Absolute Path: ", absPath); logic.append(body.key, absPath); res.send('Writting to state was successful'); });
Note: If you’re still facing the same error, then check body.path
value.