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View File JSONtext Package for working with JSON.  Uses high-speed text parsing, rather than building an intermediate representation as with prior LabVIEW JSON librari

working on it

A possibly better option is to replace your string/integer values with JSON strings, which is LabVIEW strings with <JSON> at the start of the name.  So "<JSON>Comment" rather than "Comment

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On 7/9/2020 at 5:39 AM, Porter said:

Bug? JSONText doesn't apply input default values to missing cluster items of array elements.

image.png.cfac8c824a0c9d7cb52ca3a937cbf166.pngimage.png.8ae1b813f1c246373cf99f02b3bc8356.png

I was hoping to see "Default", 1 and "2", NaN but instead get "",1 and "2",0

I think that it is due to the behavior of the Get Array Information VI.

The workaround is to convert the array elements individually as clusters:

image.png.30316820d66dc9e23dc0c3ae7f3760c8.pngimage.png.4022f34cc2d9604696e4e09bf7fe0789.png

Note: you can also do this (using the JSONpath for all array elements) because here one is specifying the element of the array (with default) rather that an empty array:

254981577_2020-09-2315_44_57-Untitled1BlockDiagramonJSONtext.lvproj_MyComputer_.png.1c8917c4a3694ddfabfb593626f8e9f3.png

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  • 5 weeks later...

I've been using this toolkit when passing data to a WebVI in LabVIEW NXG 5.0.0. It appears that the JSON parser built into NXG WebVIs is incapable of reading enums or timestamps. I am not certain if that is a limitation of the parser or the encoder. Are you able to shed any light on this drjdpowell?

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4 hours ago, Jordan Kuehn said:

It appears that the JSON parser built into NXG WebVIs is incapable of reading enums or timestamps. I am not certain if that is a limitation of the parser or the encoder.

The "Flatten to JSON" and "Unflatten from JSON" nodes in NXG WebVIs are essentially the same as the ones built into classic LabVIEW. Both are incapable of processing enums or timestamps.

As a workaround, you can create a "bridging" typedef (GType) which replaces enums and timestamps with strings. Use that with the NXG JSON parser, and then convert it to your "real" GType.

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16 minutes ago, JKSH said:

The "Flatten to JSON" and "Unflatten from JSON" nodes in NXG WebVIs are essentially the same as the ones built into classic LabVIEW. Both are incapable of processing enums or timestamps.

As a workaround, you can create a "bridging" typedef (GType) which replaces enums and timestamps with strings. Use that with the NXG JSON parser, and then convert it to your "real" GType.

Thank you for the confirmation. I have done something similar using numeric types, but it is inconvenient at best. An NXG version of this toolkit would be fantastic. 

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1 hour ago, Jordan Kuehn said:

Thank you for the confirmation. I have done something similar using numeric types, but it is inconvenient at best. An NXG version of this toolkit would be fantastic. 

Unfortunately, the NXG Web module lacks both recursion and VIs for determining the data type inside a variant.  This makes porting JSONtext to it very difficult.

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10 minutes ago, drjdpowell said:

Unfortunately, the NXG Web module lacks both recursion and VIs for determining the data type inside a variant.  This makes porting JSONtext to it very difficult.

I'm not surprised by this, but thank you for weighing in. Maybe when NXG reaches CG parity in 2050.

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  • 3 weeks later...

Hi drjdpowell,

i found an issue converting a array of clusters from text to data. 

In the JSON text is a ":" missing between key and value. Running this results in data loss (see indicator "Data NOK") without an error.

I noticed this in Version 1.3.1.84 but can confirm it also occurs in 1.4.4.89.

best regards
Thomas

image.png.608b4921c12cf5f6dfb79b84dcf8569c.png

Issue JSON Text to Array.vi

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  • 2 months later...

I skimmed through the comments and I hope this wasn't addressed. If so, my apologies.

Is there a way to limit the number of decimal places stored in a double numeric?

 

Also, is there a way to generate a JSON schema based on a LabVIEW data structure?

 

Thank you for this excellent toolkit.

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6 hours ago, Jordan Kuehn said:

Is there a way to limit the number of decimal places stored in a double numeric?

No.  Only by custom formatting the numbers into JSON yourself.  I often use single numerics, as 7 decimal places is more reasonable looking.  

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6 hours ago, Jordan Kuehn said:

Also, is there a way to generate a JSON schema based on a LabVIEW data structure?

Not sure I understand the question.  Can you rephrase it?

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11 minutes ago, drjdpowell said:

Not sure I understand the question.  Can you rephrase it?

I have a request from non-LV programmers who are using the JSON output I am providing them to provide the schema so that they can ensure they are accurately parsing the data structure. I have used a tool similar to this: https://www.liquid-technologies.com/online-json-to-schema-converter to generate it, but it is imprecise. I’d prefer to just give them the typedef file, but they have no idea what to do with that. 

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17 minutes ago, drjdpowell said:

No.  Only by custom formatting the numbers into JSON yourself.  I often use single numerics, as 7 decimal places is more reasonable looking.  

Understood, thanks!

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1 hour ago, Jordan Kuehn said:

I have a request from non-LV programmers who are using the JSON output I am providing them to provide the schema so that they can ensure they are accurately parsing the data structure. I have used a tool similar to this: https://www.liquid-technologies.com/online-json-to-schema-converter to generate it, but it is imprecise. I’d prefer to just give them the typedef file, but they have no idea what to do with that. 

Ah, you mean this then: http://json-schema.org/understanding-json-schema/, and you want a function that converts a LabVIEW Cluster/Array to a basic JSON Scheme.  

That does not exist in JSONtext but could at some point.  

 

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2 hours ago, TiborK said:

Hi, is there a chance to release build version for LabVIEW 2015?
In VIPM is allowed just >=2017.

I'm afraid it uses Malleable VIs that were introduced in 2017, meaning it can't, as a whole at least, be back ported.

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1 hour ago, Antoine Chalons said:

Would it be possible to add support for maps / sets - as if they were arrays - ?

I can really remember if they were added in LV 17 or 18 or 19....

Sets and Maps were added in 2019.  But just to throw a wrench into your dreams, you can get some interesting combinations when it comes to sets and maps.  You could have a set of maps.  You could have a map with a set for a key.  I'm just saying, you would have to plan this out very carefully.

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22 minutes ago, crossrulz said:

Sets and Maps were added in 2019.  But just to throw a wrench into your dreams, you can get some interesting combinations when it comes to sets and maps.  You could have a set of maps.  You could have a map with a set for a key.  I'm just saying, you would have to plan this out very carefully.

Very true!!

I do use nested combinations of set and map - not hugely deep but it does turn out to be very useful.

And yes it might not be trivial to handle ALL possible cases.

But let's engineer ambitiously, no?

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  • 1 month later...

Is there any way to simply get the keys or have the json structure convert into a cluster?  I've tried using the "find multiple items.vi", but nothing shows.  No errors either.

83424669_2021-03-1712_00_42-jsonparser.viFrontPanel1_.png.84c6e6c19c8658d0196044f4cf13faf5.png

 

I've also tried using "Get all objects items.vi" but looks like I have to guess at the offset and do a recursive loop.

204629551_2021-03-1712_05_26-jsonparser.viFrontPanel2_.png.82f67d56f64379b5dfcabfab90d3fb4d.png

Thank you,

Ron

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