B4J Question Error creating json and "\"

victormedranop · Feb 4, 2019

Hi i'm using this function to create a json string

B4X:

    Dim m As Map =         CreateMap("caption":caption,"type":"image/png","recipients":recipients,"content":content)
    Dim generator As JSONGenerator
    generator.Initialize(m)
[code]

but when i print the json

apears like this 

{
 "recipients": "18099897215",
 "caption": "Popola 1",
 "type": "image\/png",
 "content": "iVBORw0KGg'
}

see the type add "\" to the json string there for the web service respond with an error.

any help will be apreciated.

Victor

OliverA · Feb 4, 2019

That's the expected behavior in Java. To a solution see the answer to this stackoverflow question: https://stackoverflow.com/questions/16563579/jsonobject-tostring-how-not-to-escape-slashes

victormedranop · Feb 4, 2019

i try with replace functions but did not works and i
Dont think thats an option for me. beacuse i an sending base64 images.

Victor

still searching .......

OliverA · Feb 4, 2019

victormedranop said:
i try with replace functions but did not works and i

Code example? Output of base64 string before adding it to JSONGenerator? Output after JSONGenerator? Output after replacement function on the output of JSONGenerator?

victormedranop · Feb 4, 2019

check the function

B4X:

Sub post_image(recipients As String , caption As String, content As String )
    Dim j As HttpJob
    j.Initialize("", Me)
    Dim m As Map = CreateMap("caption":caption,"type":"image/png","recipients":recipients,"content":content)
    Dim generator As JSONGenerator
    generator.Initialize(m)
   
    Dim ss As String = generator.ToString
    ss.Replace("\","")
    Log("String to send "&ss)
    j.PostString("http://64.6.221.124:1744/img/listPOST",ss)
    j.GetRequest.SetContentType("application/json")
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Try
            Dim parser As JSONParser
            Log("Serial Result "&j.GetString)
            parser.Initialize(j.GetString)
            Dim root As Map = parser.NextObject
            Dim msg_id As String = root.Get("msg_id")
            Log($"update messages set id_message =  '${msg_id}' ,estatus = 1, fecha_recepcion = 'now()'  where telefono = '${telefono}' and mensaje = '${mensaje}'"$)
            sql1.ExecNonQuery($"update messages set id_messages =  '${msg_id}' ,status = 1, fecha_recepcion = now()  where telefono = '${telefono}' and mensaje = '${mensaje}'"$)
        Catch
            Log(LastException)
        End Try
    End If
    j.Release
    Sleep(1000)
End Sub

OliverA · Feb 4, 2019

It’s supposed to be

B4X:

ss.Replace(“\/“,”/“)

You may also need

B4X:

ss.Replace(“\\”,”\”)

Note: typing this from my phone, so don’t copy paste this since quotation marks may be wrong.

Those were the two replacement cases mentioned in the linked article.

Daestrum · Feb 5, 2019

Replace wont change the content of the string

Either use

B4X:

ss = ss.replace("\","")

or

B4X:

 Dim ss As String = generator.toString.Replace("\","")

or to save creating a new string variable change this line

B4X:

    j.PostString("http://64.6.221.124:1744/img/listPOST",ss)

to

B4X:

    j.PostString("http://64.6.221.124:1744/img/listPOST",generator.toString.Replace("\",""))

OliverA · Feb 5, 2019

@Daestrum: good catch, I missed that one. @victormedranop: The replacement pattern(s) still needs to be as I posted.

victormedranop · Feb 5, 2019

i will try tomorow. thanks

victor

victormedranop · Feb 5, 2019

i couldnt go to bed.....naaa the same error

B4X:

Log("String to send "&ss)
    j.PostString("http://64.5.122.233:3044/img/listPOST",ss.Replace("\",""))
    j.GetRequest.SetContentType("application/json")

String to send {"recipients":"18099897215","caption":"Pop1","type":"image\/png","content":"iVBORw0KuVcR7AXug1eB7lGnJNqDFNBuq8CcV6DdGsDN02GnAGlZgrmsQl2WgC6LYOcVmEvg...

Erel · Feb 5, 2019

victormedranop said:
sql1.ExecNonQuery($"update messages set id_messages = '${msg_id}' ,status = 1, fecha_recepcion = now() where telefono = '${telefono}' and mensaje = '${mensaje}'"$)

You should use parameterized queries instead.

This should work:

B4X:

StringToSend = StringToSend.Replace("\","")
Log(StringToSend)

victormedranop · Feb 5, 2019

Works..... but need to explain.

whats the diference with

B4X:

j.PostString("http://64.6.221.124:1744/img/listPOST",generator.toString.Replace("\",""))

and

ss = ss.Replace("\","")

thanks erel.

Victor

Erel · Feb 5, 2019

There is no difference. In your code you logged the message before the replacement.

victormedranop · Feb 5, 2019

UPS !!!!!

OliverA · Feb 6, 2019

victormedranop said:
ss.Replace("\","")

Even though this works in this single case, please note that this can cause issues with other cases where you may want to clean up JSONGenerator's escaping

B4X:

    Dim m As Map = CreateMap("sometext":"Java's JSON handling escapes / to \/ and \ to \\")
   Dim generator As JSONGenerator
   generator.Initialize(m)
   Log($"Original Text: ${m.Get("sometext")}"$)
   Log($"JSONGenerator.ToString: ${generator.ToString}"$)
   Log($"Replace("\",""): ${generator.ToString.Replace("\","")}"$)
   Log($"Replace("\/", "/").Replace("\\","\"): ${generator.ToString.Replace("\/", "/").Replace("\\","\")}"$)

Output:

Original Text: Java's JSON handling escapes / to \/ and \ to \\
JSONGenerator.ToString: {"sometext":"Java's JSON handling escapes \/ to \\\/ and \\ to \\\\"}
Replace("\",""): {"sometext":"Java's JSON handling escapes / to / and to "}
Replace("\/", "/").Replace("\\","\"): {"sometext":"Java's JSON handling escapes / to \/ and \ to \\"}

B4J Question Error creating json and "\"

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