B4J Question [SOLVED] Altered order when generating json from a map

mc73

mc73

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Longtime User
Hi, I'm generating a json from a map, however the final json though absolutely valid, loses the order of the items either in or out an object. This can be a bit problematic if a user decides to manually edit the json file, so it would be nice to have a solution. I will implement a function to re-organise the json, however in the mean time I'm really curious about why this may be happening.

Can anyone with a better vision on this, present the cause?

Here's the log of the original map:


[CODE lang="b4x" title="Map"](MyMap) {Description=test description, Input Port=BMT 1, Output Port=BMT 1, Sequences=[{Description=test desc, Active=Yes, Channel=0, Message Type=CC, Control Number=10, Value From=0, Value To=127, Diff From=0, Diff To=1, Operator=Or, Steps=[{Type=Keystrokes, Active=Yes, Keys=t e s t }]}]}[/CODE]

And here's the json generated by the JSONGenerator:
[CODE lang="json" title="JSON"]{
"Sequences": [
{
"Operator": "Or",
"Steps": [
{
"Type": "Keystrokes",
"Active": "Yes",
"Keys": "t e s t "
}
],
"Active": "Yes",
"Diff From": "0",
"Description": "test desc",
"Value To": "127",
"Diff To": "1",
"Channel": "0",
"Value From": "0",
"Control Number": "10",
"Message Type": "CC"
}
],
"Description": "test description",
"Input Port": "BMT 1",
"Output Port": "BMT 1"
}[/CODE]
 
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mc73 said:
Hi, I'm generating a json from a map, however the final json though absolutely valid, loses the order of the items either in or out an object. This can be a bit problematic if a user decides to manually edit the json file, so it would be nice to have a solution. I will implement a function to re-organise the json, however in the mean time I'm really curious about why this may be happening.

Can anyone with a better vision on this, present the cause?

Here's the log of the original map:


[CODE lang="b4x" title="Map"](MyMap) {Description=test description, Input Port=BMT 1, Output Port=BMT 1, Sequences=[{Description=test desc, Active=Yes, Channel=0, Message Type=CC, Control Number=10, Value From=0, Value To=127, Diff From=0, Diff To=1, Operator=Or, Steps=[{Type=Keystrokes, Active=Yes, Keys=t e s t }]}]}[/CODE]

And here's the json generated by the JSONGenerator:
[CODE lang="json" title="JSON"]{
"Sequences": [
{
"Operator": "Or",
"Steps": [
{
"Type": "Keystrokes",
"Active": "Yes",
"Keys": "t e s t "
}
],
"Active": "Yes",
"Diff From": "0",
"Description": "test desc",
"Value To": "127",
"Diff To": "1",
"Channel": "0",
"Value From": "0",
"Control Number": "10",
"Message Type": "CC"
}
],
"Description": "test description",
"Input Port": "BMT 1",
"Output Port": "BMT 1"
}[/CODE]
Click to expand...
Take a look at this post from Erel here
 
Upvote 0
walterf25 said:
Take a look at this post from Erel here
Click to expand...
Thank you very much Walter.
I don't like inserting another level of complexity in the json, so either I'll leave it as is, or try a manual generator. I will update if I come up with a good one :)
 
Upvote 0
So, I've made a custom generator, it works for me, however I haven't thoroughly tested it.
[CODE lang="b4x" title="Custom JSON Generator for keeping the order of objects"]Sub customJson(myMap As Map) As String
Return appendMap(myMap)
End Sub

Sub appendMap(myMap As Map) As String
Private json As StringBuilder
json.Initialize
json.Append("{"&CRLF)
For Each key As String In myMap.Keys
Private myObject As Object=myMap.Get(key)
json.Append(appendObject(key,myObject))
Next
Private jsonString As String=json.ToString
If jsonString.EndsWith(","&CRLF) Then
jsonString=jsonString.SubString2(0,jsonString.Length-2)
End If
jsonString=jsonString&CRLF&"}"
Return jsonString
End Sub

Sub appendList(myList As List) As String
Private json As StringBuilder
json.Initialize
json.Append("["&CRLF)
For Each myObject As Object In myList
json.Append(appendObject("",myObject))
Next
Private jsonString As String=json.ToString
If jsonString.EndsWith(","&CRLF) Then
jsonString=jsonString.SubString2(0,jsonString.Length-2)
End If
jsonString=jsonString&CRLF&"]"
Return jsonString
End Sub

Sub appendObject(key As String,myObject As Object) As String
Private json As StringBuilder
json.Initialize
If key.Length>0 Then
json.Append(escapeJSONChars(key)&": ")
End If
If myObject Is List Then
Private lst As List=myObject
json.Append(appendList(lst))
Else if myObject Is Map Then
Private anotherMap As Map=myObject
json.Append(appendMap(anotherMap))
Else
json.Append(escapeJSONChars(myObject))
End If
json.Append(","&CRLF)
Return json.ToString
End Sub

Sub escapeJSONChars (text As String) As String
Return Chr(34)&text.Replace("\","\\").Replace(Chr(34),"\"&Chr(34)).Replace(CRLF,"\n").Replace(Chr(13),"\r").Replace(TAB,"\t").Replace("/","\/")&Chr(34)
End Sub[/CODE]
 
Upvote 0
Hey don't think your code guarantees that it will save in the correct order (for maps). May be try with an orderedmap

[B4X] B4XOrderedMap - get first item, nth item and last item

B4XOrderedMap from B4XCollections, is a combination of a List with a Map. Avoid calling OrderedMap.Values unless you need to access all values, as it creates and fills a new List each call. The Keys list, on the other hand, is a list maintained by the collection and can be accessed directly...
www.b4x.com www.b4x.com
 
Upvote 0
You can use this if you have a single level Map e.g. a config file.

B4X: 
Sub AppStart (Args() As String)   
    Dim Config As Map
    Config.Initialize
    
    Config.Put("audit_web",True)
    Config.Put("ts_host","localhost")
    Config.Put("web_ignore_ext",".js|.css|.aspx")
    Config.Put("commas","1,2,3")
    Config.Put("audit_ptl", True)
    Config.Put("ts_port", 9090)   
    
    Log(MapToSortedJSONString(Config))
End Sub


Sub MapToSortedJSONString(Input As Map) As String   
    Dim Cleaned As String = Input.As(JSON).ToString
    
    Cleaned = Cleaned.SubString2(1,Cleaned.Length-1) ' Remove braces
    Cleaned = Cleaned.Trim 'Trim any empty space
    
    Dim Values As List
    Values.Initialize
    
    For Each Value As String In Regex.split(","&Chr(10),Cleaned) ' (JSON).ToString uses Chr(10) for new lines and not CRLF
        Values.Add(Value.Trim) ' Trim each line
    Next
    
    Values.Sort(True)
        
    Dim Glue As String = ","&CRLF
    Dim Indent As String = "    "
    
    Dim sb As StringBuilder
    sb.Initialize
    For Each s As String In Values
        sb.Append(Indent).Append(s).Append(Glue)
    Next
    If sb.Length > 0 Then sb.Remove(sb.Length - Glue.Length, sb.Length)
    
    Return $"{${CRLF}${sb.ToString}${CRLF}}"$
End Sub
 
Upvote 0
EnriqueGonzalez said:
Hey don't think your code guarantees that it will save in the correct order (for maps). May be try with an orderedmap

[B4X] B4XOrderedMap - get first item, nth item and last item

B4XOrderedMap from B4XCollections, is a combination of a List with a Map. Avoid calling OrderedMap.Values unless you need to access all values, as it creates and fills a new List each call. The Keys list, on the other hand, is a list maintained by the collection and can be accessed directly...
www.b4x.com www.b4x.com
Click to expand...
Hi, in this particular project the forEach in map.keys works well without the need of a b4xOrdersMap, but yes, it's true that if one tries to use this code in a more general project it may fail.
 
Upvote 0
tchart said:
You can use this if you have a single level Map e.g. a config file.

B4X: 
Sub AppStart (Args() As String)  
    Dim Config As Map
    Config.Initialize
   
    Config.Put("audit_web",True)
    Config.Put("ts_host","localhost")
    Config.Put("web_ignore_ext",".js|.css|.aspx")
    Config.Put("commas","1,2,3")
    Config.Put("audit_ptl", True)
    Config.Put("ts_port", 9090)  
   
    Log(MapToSortedJSONString(Config))
End Sub


Sub MapToSortedJSONString(Input As Map) As String  
    Dim Cleaned As String = Input.As(JSON).ToString
   
    Cleaned = Cleaned.SubString2(1,Cleaned.Length-1) ' Remove braces
    Cleaned = Cleaned.Trim 'Trim any empty space
   
    Dim Values As List
    Values.Initialize
   
    For Each Value As String In Regex.split(","&Chr(10),Cleaned) ' (JSON).ToString uses Chr(10) for new lines and not CRLF
        Values.Add(Value.Trim) ' Trim each line
    Next
   
    Values.Sort(True)
       
    Dim Glue As String = ","&CRLF
    Dim Indent As String = "    "
   
    Dim sb As StringBuilder
    sb.Initialize
    For Each s As String In Values
        sb.Append(Indent).Append(s).Append(Glue)
    Next
    If sb.Length > 0 Then sb.Remove(sb.Length - Glue.Length, sb.Length)
   
    Return $"{${CRLF}${sb.ToString}${CRLF}}"$
End Sub
Click to expand...
Hi, thank you. Unfortunately the map I work on has more levels inside.
 
Upvote 0
mc73 said:
Note that in B4X CRLF is in fact the chr(10).
Click to expand...
Thanks for pointing this out, I had never noticed this.

I always assumed it was Chr(13) + Chr(10) since the name is CRLF

The reason I usually replace Chr(10) with Chr(13) & Chr(10) is that some versions of Notepad on Windows wont show the new lines correctly.

I never noticed this (as I use Notepad++) until a customer pointed out that it was difficult to update a config file as it was all on one line.

B4X: 
ConfigString = ConfigString.Replace(Chr(10), Chr(13) & Chr(10))
 
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