I'm trying to set the user agent for a request with XmlRead. I googled a lot about this and couldn't find the answer. Here is my chunk of code:
Dim RssData As DataSet
Dim Title As String
Dim Url As String
Dim Stream As String
Dim buffer As Integer
RssData = New DataSet()
RssData.ReadXml("http://localhost/user_agent.php")
buffer = 0
For Each RssRow As DataRow In RssData.Tables("entry").Rows
Title = Microsoft.VisualBasic.Left(RssRow.Item("title").ToString, 30)
Stream += Title & vbCrLf
Next
LinkLabel3.Text = Stream
For Each RssRow As DataRow In RssData.Tables("entry").Rows
Title = Microsoft.VisualBasic.Left(RssRow.Item("title").ToString, 30)
Url = RssRow.Item("url").ToString
LinkLabel3.Links.Add(buffer, Title.Length, Url)
buffer = buffer + Title.Length + 2
Next
The part of the code that actually performs the web request is buried pretty deep so you'd have to inherit a bunch of code to do what you asked for. Instead, let me suggest a different path, download the XML on your own with code that's easy to set that header, and then load that into the dataset. The WebClient class lets you set arbitrary headers and has a simple DownloadString method. Once you've got that you can wrap it in a MemoryStream and pass that into ReadXml(). (I couldn't find a way to read the XML as a string, that's why I was forced to read it as Stream.)
''//Will hold our downloaded XML
Dim MyXml As String
''//Create a webclient to download our XML
Using WC As New System.Net.WebClient()
''//Manually set the user agent header
WC.Headers.Add("user-agent", "your user agent here")
''//Download the XML
MyXml = WC.DownloadString("http://localhost/user_agent.php")
End Using
''//Create our dataset object
Dim RssData As New DataSet()
''//There is no direct method to load XML as a string (at least that I could find) so we will
''// convert it to a byte array and load it into a memory stream
Dim Bytes As Byte() = System.Text.Encoding.UTF8.GetBytes(MyXml)
Using MS As New System.IO.MemoryStream(Bytes)
''//Load the stream into the reader
RssData.ReadXml(MS)
End Using
''//Your code continues normally here
Related
Please see part of the code used to save response as a string to resultData variable:
Using response As WebResponse = request.GetResponse()
Dim responseStream As IO.Stream = response.GetResponseStream()
Dim sr As New IO.StreamReader(responseStream)
resultData = sr.ReadToEnd()
It works correctly.
I have one case where the output is a binary file. How can I modify this code to save the reponse as a binary ResultData variable?
Thank you in advance for your support.
There is many ways to do that. This one, is one of those. (This one help you also to show the progress)
However (as advice) to monitoring progress there exists better approaches like Async methods etc.
In the example below I’m going to show you how to save e WebRequest as binary data.
Note that, I’m based on your code and what you want, but, as I said before there exists different better approaches.
'here the file you want to save
Dim LocalFilePath As String = "C:\Users\MyUser\Documents\FolderXYZ\yourfileName.extension"
Using reader As IO.Stream = request.GetResponse.GetResponseStream
Using writer As IO.Stream = New IO.FileStream(LocalFilePath, IO.FileMode.OpenOrCreate, IO.FileAccess.ReadWrite)
Dim b(1024 * 2) As Byte
Dim buffer As Integer = b.Length
Do While buffer <> 0
buffer = reader.Read(b, 0, b.Length)
writer.Write(b, 0, buffer)
writer.Flush()
Loop
End Using
End Using
Am trying to copy my image value to text file. my code is below.
If fldtype = "System.Byte[]" Then
Dim bits As Byte() = CType(drow(dc), Byte())
Using ms As New MemoryStream(bits)
Dim sw As New StreamWriter(ms)
Dim sr As New StreamReader(ms)
Dim myStr As String = sr.ReadToEnd()
MessageBox.Show(myStr)
fldvalue = fldvalue + "," + myStr
End Using
I find this to be one of the easiest ways to write a Byte[] to a string:
If fldtype = "System.Byte[]" Then
Dim bits As Byte() = CType(drow(dc), Byte())
Dim s As String = Convert.ToBase64String(bits)
End If
Works in reverse, too:
Dim newBytes() As Byte = Convert.FromBase64String(s)
The answer linked in the original comments could prove to be better options. Answering these questions would go a long way:
Why write an image out to text in the first place?
What do you mean to do with it once it's there?
Do you need to be able to retrieve that string and re-form the original image?
Question #3 is especially important because the information you are capturing matters when it comes to image format information. That could be lost, making it difficult to reconstitute the original image 100%.
I have a web service,which return data in byte array.Now i want to read that data in my console project.How can i do that,i already add the desire references to access that web service.I am using vb.net VS2012.Thanks.My web service method is as follow.
Public Function GetFile() As Byte()
Dim response As Byte()
Dim filePath As String = "D:\file.txt"
response = File.ReadAllBytes(filePath)
Return response
End Function
Something like,
Dim result As String
Using (Dim data As New MemoryStream(response))
Using (Dim reader As New StreamReader(data))
result = reader.ReadToEnd()
End Using
End Using
if you knew the encoding, lets say it was UTF-8 you could do,
Dim result = System.Text.UTF8Encoding.GetString(response)
Following on from your comments, I think you are asserting this.
Dim response As Byte() 'Is the bytes of a Base64 encoded string.
So, we know all the bytes will be valid ASCII (because its Base64,) so the string encoding is interchangable.
Dim base64Encoded As String = System.Text.UTF8Encoding.GetString(response)
Now, base64Encoded is the string Base64 representation of some binary.
Dim decodedBinary As Byte() = Convert.FromBase64String(base64Encoded)
So, we've changed the encoded base64 into the binary it represents. Now, because I can see that in your example, you are reading a file called "D:/file.txt" I'm going to make the assumption that the contents of the file is a character encoded string, but I don't know the encoding of the string. The StreamReader class has some logic in the constructor that can make an educated guess at character encoding.
Dim result As String
Using (Dim data As New MemoryStream(decodedBinary))
Using (Dim reader As New StreamReader(data))
result = reader.ReadToEnd()
End Using
End Using
Hopefully, now result contains the context of the text file.
I thought this would be an easy task but I seem to have gotten lost in a rabbit hole.
I am trying to convert a class to XML and then a byte array in order to send it as the content of a HTTPWebRequest for a WCF Restful webservice. My code will return the class as XML in the Byte Array but the format is incorrect. The XML looks like this:
<?xml version="1.0" encoding="utf-8"?><Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><FirstName>Richard</FirstName><LastName>Cranium</LastName></Person>
I was attempting to use the OmitXmlDeclaration method thinking this would eliminate the extra declarations but it does not work with the xmltextwriter object and when I use the xmlwriterobject I can't determine how convert the outcome to a Byte array.
Here is my code:
Private Shared Function GenerateXMLPersonAsByte(strFirstName As String, strLastName As String) As Byte()
' This should serialize this to a byte array
Dim p As New Person()
p.FirstName = strFirstName
p.LastName = strLastName
' Want to use this with the xmlTextWriter but it does not support the property it is to be used with the XMLWriter instead
'Dim settings As XmlWriterSettings = New XmlWriterSettings()
'settings.OmitXmlDeclaration = True
'settings.ConformanceLevel = ConformanceLevel.Fragment
'settings.CloseOutput = False
' Create the XmlWriter object and write some content.
Dim mStream As New MemoryStream()
Dim ser As New XmlSerializer(GetType(Person))
Dim xmlTW As New XmlTextWriter(mStream, Encoding.UTF8)
ser.Serialize(xmlTW, p)
mStream = DirectCast(xmlTW.BaseStream, MemoryStream)
mStream.Close()
Return mStream.ToArray()
End Function
What must I do in order to get the XML with the correct opening tag?
or
How do I get the output from the XmlTextWriter object to a byte array?
I can't answer the whole question, but convert to string first
Dim myXmlString As String
Dim myStringWriter As New StringWriter()
Dim myXmlTextWriter As XmlTextWriter = New XmlTextWriter(myStringWriter)
'Write XML, and then flush the writer...
myXmlTextWriter.Flush()
'Return text from string writer...
myXmlString = myStringWriter.ToString()
'Close the Objects...
myStringWriter.Close()
myXmlTextWriter.Close()
then convert to byte using (sorry, C#, but you get the .NET call)
byte[] data = ASCIIEncoding.UTF8.GetBytes(myXmlString);
Reading binary data out of the database, and I need to convert it back into a Digital Persona fingerprint template. I'm not familiar with serialization and deserialization, so I could use a bit of help. Here's what I tried:
Dim rsBioData As SqlDataReader = SQL.ExecuteReader
Dim byteTemplate As Byte
Dim memStreamTemplate As MemoryStream
If rsBioData.HasRows Then
While rsBioData.Read
byteTemplate = rsBioData("BiometricData")
memStreamTemplate = New MemoryStream(byteTemplate)
Me.Template = DirectCast(template.DeSerialize(memStreamTemplate), DPFP.Template)
End While
End If
rsBioData.Close()
I receive an error that template.DeSerialize(memStreamTemplate) does not create a value.
For kicks, here's how I serialized the object to place it into the database. I assume this part is working, since the binary data shows up in SQL server--just can't read it back out to see.
Dim str As New MemoryStream
Enroller.Template.Serialize(str)
Dim serializedTemplate As Byte() = str.ToArray()
SQL.Parameters.AddWithValue("biometricData", serializedTemplate)
Thanks
Here's how I was finally able to do it. I was SO close the first time around.
byteTemplate = rsBioData("BiometricData")
memStreamTemplate = New MemoryStream(byteTemplate)
Me.Template.DeSerialize(memStreamTemplate)