I have a json which has the a particular format, I wanted to extract data from it, but it contains ':' in its key value which is giving error while printing
metadata:
{
'A:B':'string'
}
I have tried to take it in another varibale stills it gives error:
text='A'+':'+'B';
console.log(metadata.text);
//console.log(metadata.A:B);
You can simply use jsonVariableName["ObjectName"] instead of sonVariableName.ObjectName
var metadata = {
'A:B':'string'
};
console.log(metadata["A:B"]);
Also I found you mention code as:
metadata:{...}
Which I think will be:
metadata = {...}
Related
how do I use a nodejs var inside a json statement, I dont realy have the required vocabulary to explain but here is my simplifyed code:
test.json:
{
"test1":["test1.1", "test1.2"],
"test2":["test2.1", "test2.2"]
}
test.js:
const json = require("./test.json")
function myFunction(TYPE){
return(json.TYPE[0])
}
console.log(myFunction("test1"))
as I use the "type" var it tries to uses it as an json statement or object but obviously there is no "type" there only is "test1" and "test2" but it interprets as "type" instead
Brackets to access the variable key should work
function myFunction(TYPE){
return(json[TYPE][0])
}
In JavaScript, json objects are pretty much same as plain JS objects. You need to use string as an index to access properties:
// This could be your json file, its almost the same
// Just require it like you did instead of using const JSON like i am
const json = {
"test1":["test1.1", "test1.2"],
"test2":["test2.1", "test2.2"]
}
function myFunction(TYPE){
// Access the json by using keyword directly as index string
return(json[TYPE])
// because TYPE is a string, TYPE[0] would mean first letter of TYPE string
}
function myFunctionDeeper(TYPE){
// To access a field and array in that field
return(json[TYPE][0])
}
console.log(myFunction("test1"))
console.log(myFunctionDeeper("test1"))
// example for what happens when accessing string by index
console.log("test1"[0])
Read more about objects here
So in my js-code I have this line:
var _script = {
_script: {
script: {
lang: 'painless',
source: `
"""
if(1>2){
params._source.id;
}
else{
params._source.id;
}
"""
`
},
type: 'string',
order: params._source.id
}
}
This will fail. I see in the log this error message:
,\"reason\":\"unexpected token ['\\\"\\\\n if(1>2){\\\\n params._source.id;\\\\n }\\\\n else{\\\\n params._source.id;\\\\n }\\\\n \\\"'] was expecting one of [{<EOF>, ';'}].\"}}}]},
I have tried first to have without tilde-character. And then it also fails.
I then tried to have tilde at the beginning, something like:
var _script = `{
Thing is that the final json that will be sent to elastic is not shown in the code above. So "_script" is only a little part of all the json.
I was wondering if I added the tilde at the very beginning and end of the whole json. Maybe it could work? I need to work it out where it is.
But just in theory: do you think the problem is there? Putting the tilde around all the json? Or is it something else?
The triple " is not valid JSON, it only works internally to the Elastic stack (i.e. from Kibana Dev Tools to ES).
The way I usually do it from Node.js is to add each line to an array and then I join that array, like this:
const code = [];
code.push("if(1>2){");
code.push("params._source.id;");
code.push("} else {");
code.push("params._source.id;");
code.push("}");
source = code.join(" ");
It's not super legible, I admit. Another way is to use stored scripts so you can simple reference your script by ID in Node.js.
The following is confusing me a lot. I have been spending quite a bit of time trying to understand why collection.find() doesn't work with regex passed as an object. The regex match is coming over HTTP wrapped in the body of a POST request. Then I try to gather the query (in string format) and perform the query. The problem seems to be that unless the regex is written inside Node without quotes, it won't work. That is, it must be a literal without quotes.
For example, the following works fine:
var query1 = {
company: {
'$regex': /goog/
}
};
collection.find(query1, {}).toArray(function (err, docs) {
// Got results back. Awesome.
});
However, if the data comes wrapped in an object, it doesn't return anything. I suspect it's because the value gets quoted behind the scenes (i.e. "/goog/"):
// Assume
var query2 = {
company: {
'$regex': query.company
}
};
collection.find(query2, {}).toArray(function (err, docs) {
// Got nothing back.
});
I have tested it with the mongo shell and I can confirm the following:
// Returns 5 results
db.getCollection("contacts").find( { "company": /goog/ } )
// Doesn't match anything
db.getCollection("contacts").find( { "company": "/goog/" } )
Furthermore, I just discovered the following: if I write the value with quotes
// Works fine
var companyRegex = {'$regex': /goog/};
var query3 = {
company: companyRegex
};
So technically, a "literal" regex without quotes wrapped in an object works fine. But if it's a string, it won't work. Even after trying to replace the double-quotes and single-quotes with nothing (i.e. essentially removing them.)
Any idea how can I get the regex match be passed verbatim to find()? I've researched it, finding lots of potential solutions, alas it's not working for me.
Thanks in advance!
Let me focus on one line of your post. This is where the problem might be:
The regex match is coming over HTTP wrapped in the body of a POST request.
This seems problematic because:
The only structures that survive serialization between client/server are:
boolean
number
string
null *
objects and arrays containing these basic types
objects and arrays containing object and arrays [of more obj/array] of these basic types
Regexp, Date, Function, and a host of others require reconstruction, which means
passing a string or pair of strings for the match and option components of the Regexp and running Regexp() on the receiving end to reconstruct.
Regexp gets a bit messy because Regexp.toString() and Regexp() do not appear to be inverses of each others: /someMatch/.toString() is "/someMatch/" but RegExp("/someMatch/") is //someMatch// and what was needed instead to rebuild the regexp was just RegExp("someMatch"), which is /someMatch/. I hope this helps.
JSON.stringify(/someMatch/) is {} (at least on Chrome).
So instead of trying to build a general transport, I recommend re instantiating a particular field as a regexp.
* Irrelevant note: (null is fine but undefined is peculiar. JSON won't stringify undefineds in objects and turns undefined into null in Arrays. I recognize this isn't part of your problem, just trying to be complete in describing what can be serialized.)
This is very odd... I'm using populate() with a ref to fill in an array within my schema, but then the properties are inaccessible. In other words, the schema is like this:
new Model('User',{
'name': String,
'installations': [ {type: String, ref: 'Installations'} ],
'count': Number,
}
Of course, Insallations is another model.
Then I find & populate a set of users...
model.find({count: 0}).populate('installations').exec( function(e, d){
for(var k in d)
{
var user = d[k];
for(var i in user.installations)
{
console.log(user.installations[i]);
}
}
} );
So far so good! I see nice data printed out, like this:
{ runs: 49,
hardware: 'macbookpro10,1/x86_64',
mode: 'debug',
version: '0.1' }
However, if I try to actually ACCESS any of those properties, they're all undefined! For example, if I add another console log:
console.log(user.installations[i].mode);
Then I see "undefined" printed for this log.
If I try to operate on the object, like this:
Object.keys(user.installations[i]).forEach(function(key) { } );
Then I get a typical "[TypeError: Object.keys called on non-object]" error, indicating that user.installations[i] is not an object (even though it is outputted to the console as if it were). So, I even tried something ugly like...
var install = JSON.parse(JSON.stringify(user.installations[i]));
console.log(install, install.mode);
And, again, the first output (install) is a nice object containing the property 'mode'... but the 2nd output is undefined.
What gives?
Finally, I solved this...
I tried doing a console.log(typeof user.installations[i]); and got "string" as the output. This seemed odd, given that printing the object directly created console output (above) that looked like a normal object, not a string. So, I tried doing a JSON.parse(); on the object, but received the error "SyntaxError: Unexpected token r"
Finally, I realized what was going on. The "pretty console output" I described above was the result of a string formatted with \n (newlines). I had not expected that, for whatever reason. The JSON.parse() error is due to the fact that there is a known necessity with the node.js parser when attempting to parse object keys without quotations; see the SO question here:
Why does JSON.parse('{"key" : "value"}') do just fine but JSON.parse('{key : "value"}') doesn't? .
Specifically, note that the JSON parser in my case is failing on the character 'r', the fist character of "runs," which is the first key in my JSON string (above). At first I was afraid I needed to get a custom JSON parser, but then the problem hit me.
Look back to my original schema. I used a String-type to define the installation ref, because the array field was storing the installations's _id property as a String. I assume the .populate() field is converting the object to a String on output.
Finally, I looked at the Mongoose docs a little closer and realized I'm supposed to be referencing the objects based upon Schema.ObjectID. This explains everything, but certainly gives me some fixing to do in my schemas and code elsewhere...
I am using simpldb and am trying to save rahul' mehta in simpledb but it is giving me error below :
Code :
function htmlEscape(text) {
return text.replace(/&/g,'&').
replace(/</g,'<').
replace(/"/g,'"').
replace(/'/g,''');
}
console.log(params.filename);
if (params.filename!=undefined) params.filename=htmlEscape(params.filename);
console.log(sys.inspect(params));
sdb.putItem(domain, params.objectid, params, function( error ) {
});
Output :
rahul' mehta
{
filename: 'rahul' mehta',
}
Error :
{"event":"error","errno":"InvalidQueryExpression","message":"The specified query expression syntax is not valid.","queueno":7}
Why this error is coming , how can i solve it ?
This error is because you are trying to run Amazon SimpleDB SELECT Query and syntax of that query is wrong. This may be because in query -- Attribute Value -- must be unclosed with single quotes i.e. 'Attribute Value', and again if -- Domain Name -- and -- Attribute Name -- contains any special characters then they must be unclosed with acute i.e Domain Name OR Attribute Name. I think you are able to save rahul' mehta but when you are trying to get that saved attribute-value, you are getting this error. http://www.sdbexplorer.com/