Using System.Net.Http I was able to construct the form request as a proof of concept using MultipartFormDataContent
Now initially when I tested it, I received 403 Forbidden response but I guessed that was to be expected given my location and that the endpoint might be region locked.
Raw Fiddler response
HTTP/1.1 403 Forbidden
Date: Sat, 27 Oct 2018 01:37:09 GMT
Server: IIS
Content-Length: 225
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html; charset=iso-8859-1
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>403 Forbidden</title>
</head><body>
<h1>Forbidden</h1>
<p>You don't have permission to access /cgi-bin/aps_cacheWEB.sh
on this server.</p>
</body></html>
I was wrong and the forbidden appeared to be the default response for bad requests as you commented that you received the same forbidden error from within the region. So back to the drawing board I went.
I then copied the example HTML form locally and then proceeded to compare the requests from the form (which did actually work) and my code. Gradually making changes to match I was finally able to get a 200 OK response, but the body of the response was empty.
Apparently there was an issue with the server interpreting the boundary in the content type header if it is wrapped in quotes boundary="...".
After more adjustments it then started returning a message based on the content dispositions generated.
HTTP/1.1 200 OK
Date: Sat, 27 Oct 2018 19:55:11 GMT
Server: IIS
Serial: 10.145
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/plain; charset=ISO-8859-2
Content-Length: 169
Multiple definitions of VSS_SERV encountered in input.
If you're trying to do this intentionally (such as with select),
the variable must have a "List" suffix.
So it turns out that the XML API is expecting the request to be in a very specific format. Deviate from that and the request fails.
The MultipartFormDataContent was not generating the request correctly and this caused the server to not behave as expected. Other headers were being placed before the Content-Disposition headers of the parts and the Content-Disposition parameters were also not being enclosed in quotes. So by not including the content-type it in the parts and making sure the content-disposition headers were generated correctly eventually fixed the problem.
It is important to note the order of how the headers are added to the content so that the Content-Disposition header is set first for each part.
Working Code that generates the request in the desired format and gets the XML data.
[Test]
public async Task Post_Form() {
//Arrange
var stream = getXml();
var fileContent = new StreamContent(stream);
fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") {
Name = @"""filename""",
FileName = @"""req-details.xml""",
};
fileContent.Headers.ContentType = new MediaTypeHeaderValue("text/xml");
var stringContent = new ByteArrayContent(Encoding.UTF8.GetBytes("ZVWSBJXML"));
stringContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data") {
Name = @"""VSS_SERV""",
};
//could have let system generate it but wanteed to rule it out as a problem
var boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x", NumberFormatInfo.InvariantInfo);
var form = new MultipartFormDataContent(boundary);
//FIX: boundary quote issue
var contentType = form.Headers.ContentType.Parameters.First(o => o.Name == "boundary");
contentType.Value = contentType.Value.Replace("\"", String.Empty);
form.Add(stringContent);
form.Add(fileContent);
//var data = await form.ReadAsStringAsync(); //FOR TESTING PORPOSES ONLY!!
var client = createHttpClient("http://www.rzp.cz/");
//Act
var response = await client.PostAsync("cgi-bin/aps_cacheWEB.sh", form);
var body = await response.Content.ReadAsStringAsync();
//Assert
response.IsSuccessStatusCode.Should().BeTrue();
body.Should().NotBeEmpty();
var document = XDocument.Parse(body); //should be valid XML
document.Should().NotBeNull();
}
The code above generated the following request, which I extracted using fiddler (Pay close attention to the working format)
POST http://www.rzp.cz/cgi-bin/aps_cacheWEB.sh HTTP/1.1
User-Agent: System.Net.Http.HttpClient
Accept-Language: en-US, en; q=0.9
Accept: text/xml, application/xml
Cache-Control: max-age=0
Content-Type: multipart/form-data; boundary=---------------------------8d63c301f3e044f
Host: www.rzp.cz
Content-Length: 574
Accept-Encoding: gzip, deflate
Connection: Keep-Alive
-----------------------------8d63c301f3e044f
Content-Disposition: form-data; name="VSS_SERV"
ZVWSBJXML
-----------------------------8d63c301f3e044f
Content-Disposition: form-data; name="filename"; filename="req-details.xml"
Content-Type: text/xml
<?xml version="1.0" encoding="iso-8859-2"?>
<VerejnyWebDotaz xmlns="urn:cz:isvs:rzp:schemas:VerejnaCast:v1" version="2.8">
<Kriteria>
<IdentifikacniCislo>75848899</IdentifikacniCislo>
<PlatnostZaznamu>0</PlatnostZaznamu>
</Kriteria>
</VerejnyWebDotaz>
-----------------------------8d63c301f3e044f--
Which was able to get the following response.
HTTP/1.1 200 OK
Date: Sat, 27 Oct 2018 21:17:50 GMT
Server: IIS
Serial: 10.145
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/xml;charset=ISO-8859-2
Content-Length: 931
<?xml version='1.0' encoding='iso-8859-2'?>
<VerejnyWebOdpoved xmlns="urn:cz:isvs:rzp:schemas:VerejnaCast:v1" version="2.8">
<Datum>27.10.2018</Datum>
<Kriteria>
<IdentifikacniCislo>75848899</IdentifikacniCislo>
<PlatnostZaznamu>0</PlatnostZaznamu>
</Kriteria>
<PodnikatelSeznam>
<PodnikatelID>212fbf8314e01506b0d7</PodnikatelID>
<ObchodniJmenoSeznam Popis="Jméno a příjmení:">Filip Zrůst</ObchodniJmenoSeznam>
<IdentifikacniCisloSeznam Popis="Identifikační číslo osoby:">75848899</IdentifikacniCisloSeznam>
<TypPodnikatele Popis="Typ podnikatele:">Fyzická osoba</TypPodnikatele>
<AdresaPodnikaniSeznam Popis="Adresa sídla:">Vlašská 358/7, 118 00, Praha 1 - Malá Strana</AdresaPodnikaniSeznam>
<RoleSubjektu Popis="Role subjektu:">podnikatel</RoleSubjektu>
<EvidujiciUrad Popis="Úřad příslušný podle §71 odst.2 živnostenského zákona:">Úřad městské části Praha 1</EvidujiciUrad>
</PodnikatelSeznam>
</VerejnyWebOdpoved>
From there it should be small work to parse the resulting XML as needed.
Supporting code
Generate or load the stream of the XML for the form
private static Stream getXml() {
var xml = @"<?xml version=""1.0"" encoding=""ISO-8859-2""?>
<VerejnyWebDotaz
xmlns=""urn:cz:isvs:rzp:schemas:VerejnaCast:v1""
version=""2.8"">
<Kriteria>
<IdentifikacniCislo>75848899</IdentifikacniCislo>
<PlatnostZaznamu>0</PlatnostZaznamu>
</Kriteria>
</VerejnyWebDotaz>";
var doc = XDocument.Parse(xml);//basically to validate XML
var stream = new MemoryStream();
doc.Save(stream);
stream.Position = 0;
return stream;
}
Was gradually able to whittle down the headers needed for a successful request after find the match that worked. Try removing others gradually to test if more can be removed safely to reduce the amount of unnecessary code needed.
private static HttpClient createHttpClient(string baseAddress) {
var handler = createHandler();
var client = new HttpClient(handler);
client.BaseAddress = new Uri(baseAddress);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.TryAddWithoutValidation("User-Agent", "System.Net.Http.HttpClient");
client.DefaultRequestHeaders.TryAddWithoutValidation("Accept-Language", "en-US,en;q=0.9");
client.DefaultRequestHeaders.TryAddWithoutValidation("Accept", "text/xml,application/xml");
client.DefaultRequestHeaders.ExpectContinue = false;
client.DefaultRequestHeaders.ConnectionClose = false;
client.DefaultRequestHeaders.CacheControl = new CacheControlHeaderValue() {
MaxAge = TimeSpan.FromSeconds(0)
};
return client;
}
private static HttpClientHandler createHandler() {
var handler = new HttpClientHandler();
// if the framework supports automatic decompression set automatic decompression
if (handler.SupportsAutomaticDecompression) {
handler.AutomaticDecompression = System.Net.DecompressionMethods.GZip |
System.Net.DecompressionMethods.Deflate;
}
return handler;
}
While I chose to use the asynchronous API of System.Net.Http, I found a similar question
Reference UploadFile with POST values by WebClient
With an answer that was done using WebClient that could be adapted to your question so that a request can be constructed similar to what was produced above.
I tried testing that one as well but got into the same forbidden error. Now that the correct format is know you should also be able to correctly craft a working request using WebClient/WebRequest
