#
#
# Nimrod's Runtime Library
# (c) Copyright 2010 Dominik Picheta, Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements a simple HTTP client that can be used to retrieve
## webpages/other data.
##
## Retrieving a website
## ====================
##
## This example uses HTTP GET to retrieve
## ``http://google.com``
##
## .. code-block:: nimrod
## echo(getContent("http://google.com"))
##
## Using HTTP POST
## ===============
##
## This example demonstrates the usage of the W3 HTML Validator, it
## uses ``multipart/form-data`` as the ``Content-Type`` to send the HTML to
## the server.
##
## .. code-block:: nimrod
## var headers: string = "Content-Type: multipart/form-data; boundary=xyz\c\L"
## var body: string = "--xyz\c\L"
## # soap 1.2 output
## body.add("Content-Disposition: form-data; name=\"output\"\c\L")
## body.add("\c\Lsoap12\c\L")
##
## # html
## body.add("--xyz\c\L")
## body.add("Content-Disposition: form-data; name=\"uploaded_file\";" &
## " filename=\"test.html\"\c\L")
## body.add("Content-Type: text/html\c\L")
## body.add("\c\L<html><head></head><body><p>test</p></body></html>\c\L")
## body.add("--xyz--")
##
## echo(postContent("http://validator.w3.org/check", headers, body))
##
## SSL/TLS support
## ===============
## This requires the OpenSSL library, fortunately it's widely used and installed
## on many operating systems. httpclient will use SSL automatically if you give
## any of the functions a url with the ``https`` schema, for example:
## ``https://github.com/``, you also have to compile with ``ssl`` defined like so:
## ``nimrod c -d:ssl ...``.
##
## Timeouts
## ========
## Currently all functions support an optional timeout, by default the timeout is set to
## `-1` which means that the function will never time out. The timeout is
## measured in miliseconds, once it is set any call on a socket which may
## block will be susceptible to this timeout, however please remember that the
## function as a whole can take longer than the specified timeout, only
## individual internal calls on the socket are affected. In practice this means
## that as long as the server is sending data an exception will not be raised,
## if however data does not reach client within the specified timeout an ETimeout
## exception will then be raised.
import sockets, strutils, parseurl, parseutils, strtabs
type
TResponse* = tuple[
version: string,
status: string,
headers: PStringTable,
body: string]
EInvalidProtocol* = object of ESynch ## exception that is raised when server
## does not conform to the implemented
## protocol
EHttpRequestErr* = object of ESynch ## Thrown in the ``getContent`` proc
## and ``postContent`` proc,
## when the server returns an error
const defUserAgent* = "Nimrod httpclient/0.1"
proc httpError(msg: string) =
var e: ref EInvalidProtocol
new(e)
e.msg = msg
raise e
proc fileError(msg: string) =
var e: ref EIO
new(e)
e.msg = msg
raise e
proc parseChunks(s: TSocket, timeout: int): string =
result = ""
var ri = 0
while true:
var chunkSizeStr = ""
var chunkSize = 0
s.readLine(chunkSizeStr, timeout)
var i = 0
if chunkSizeStr == "":
httpError("Server terminated connection prematurely")
while true:
case chunkSizeStr[i]
of '0'..'9':
chunkSize = chunkSize shl 4 or (ord(chunkSizeStr[i]) - ord('0'))
of 'a'..'f':
chunkSize = chunkSize shl 4 or (ord(chunkSizeStr[i]) - ord('a') + 10)
of 'A'..'F':
chunkSize = chunkSize shl 4 or (ord(chunkSizeStr[i]) - ord('A') + 10)
of '\0':
break
of ';':
# http://tools.ietf.org/html/rfc2616#section-3.6.1
# We don't care about chunk-extensions.
break
else:
httpError("Invalid chunk size: " & chunkSizeStr)
inc(i)
if chunkSize <= 0: break
result.setLen(ri+chunkSize)
var bytesRead = 0
while bytesRead != chunkSize:
let ret = recv(s, addr(result[ri]), chunkSize-bytesRead, timeout)
ri += ret
bytesRead += ret
s.skip(2, timeout) # Skip \c\L
# Trailer headers will only be sent if the request specifies that we want
# them: http://tools.ietf.org/html/rfc2616#section-3.6.1
proc parseBody(s: TSocket, headers: PStringTable, timeout: int): string =
result = ""
if headers["Transfer-Encoding"] == "chunked":
result = parseChunks(s, timeout)
else:
# -REGION- Content-Length
# (http://tools.ietf.org/html/rfc2616#section-4.4) NR.3
var contentLengthHeader = headers["Content-Length"]
if contentLengthHeader != "":
var length = contentLengthHeader.parseint()
result = newString(length)
var received = 0
while true:
if received >= length: break
let r = s.recv(addr(result[received]), length-received, timeout)
if r == 0: break
received += r
if received != length:
httpError("Got invalid content length. Expected: " & $length &
" got: " & $received)
else:
# (http://tools.ietf.org/html/rfc2616#section-4.4) NR.4 TODO
# -REGION- Connection: Close
# (http://tools.ietf.org/html/rfc2616#section-4.4) NR.5
if headers["Connection"] == "close":
var buf = ""
while True:
buf = newString(4000)
let r = s.recv(addr(buf[0]), 4000, timeout)
if r == 0: break
buf.setLen(r)
result.add(buf)
proc parseResponse(s: TSocket, getBody: bool, timeout: int): TResponse =
var parsedStatus = false
var linei = 0
var fullyRead = false
var line = ""
result.headers = newStringTable(modeCaseInsensitive)
while True:
line = ""
linei = 0
s.readLine(line, timeout)
if line == "": break # We've been disconnected.
if line == "\c\L":
fullyRead = true
break
if not parsedStatus:
# Parse HTTP version info and status code.
var le = skipIgnoreCase(line, "HTTP/", linei)
if le <= 0: httpError("invalid http version")
inc(linei, le)
le = skipIgnoreCase(line, "1.1", linei)
if le > 0: result.version = "1.1"
else:
le = skipIgnoreCase(line, "1.0", linei)
if le <= 0: httpError("unsupported http version")
result.version = "1.0"
inc(linei, le)
# Status code
linei.inc skipWhitespace(line, linei)
result.status = line[linei .. -1]
parsedStatus = true
else:
# Parse headers
var name = ""
var le = parseUntil(line, name, ':', linei)
if le <= 0: httpError("invalid headers")
inc(linei, le)
if line[linei] != ':': httpError("invalid headers")
inc(linei) # Skip :
linei += skipWhitespace(line, linei)
result.headers[name] = line[linei.. -1]
if not fullyRead:
httpError("Connection was closed before full request has been made")
if getBody:
result.body = parseBody(s, result.headers, timeout)
else:
result.body = ""
type
THttpMethod* = enum ## the requested HttpMethod
httpHEAD, ## Asks for the response identical to the one that would
## correspond to a GET request, but without the response
## body.
httpGET, ## Retrieves the specified resource.
httpPOST, ## Submits data to be processed to the identified
## resource. The data is included in the body of the
## request.
httpPUT, ## Uploads a representation of the specified resource.
httpDELETE, ## Deletes the specified resource.
httpTRACE, ## Echoes back the received request, so that a client
## can see what intermediate servers are adding or
## changing in the request.
httpOPTIONS, ## Returns the HTTP methods that the server supports
## for specified address.
httpCONNECT ## Converts the request connection to a transparent
## TCP/IP tunnel, usually used for proxies.
when not defined(ssl):
type PSSLContext = ref object
let defaultSSLContext: PSSLContext = nil
else:
let defaultSSLContext = newContext(verifyMode = CVerifyNone)
proc request*(url: string, httpMethod = httpGET, extraHeaders = "",
body = "",
sslContext: PSSLContext = defaultSSLContext,
timeout = -1, userAgent = defUserAgent): TResponse =
## | Requests ``url`` with the specified ``httpMethod``.
## | Extra headers can be specified and must be seperated by ``\c\L``
## | An optional timeout can be specified in miliseconds, if reading from the
## server takes longer than specified an ETimeout exception will be raised.
var r = parseUrl(url)
var headers = substr($httpMethod, len("http"))
headers.add(" /" & r.path & r.query)
headers.add(" HTTP/1.1\c\L")
add(headers, "Host: " & r.hostname & "\c\L")
if userAgent != "":
add(headers, "User-Agent: " & userAgent & "\c\L")
add(headers, extraHeaders)
add(headers, "\c\L")
var s = socket()
var port = TPort(80)
if r.scheme == "https":
when defined(ssl):
sslContext.wrapSocket(s)
else:
raise newException(EHttpRequestErr,
"SSL support is not available. Cannot connect over SSL.")
port = TPort(443)
if r.port != "":
port = TPort(r.port.parseInt)
if timeout == -1:
s.connect(r.hostname, port)
else:
s.connect(r.hostname, port, timeout)
s.send(headers)
if body != "":
s.send(body)
result = parseResponse(s, httpMethod != httpHEAD, timeout)
s.close()
proc redirection(status: string): bool =
const redirectionNRs = ["301", "302", "303", "307"]
for i in items(redirectionNRs):
if status.startsWith(i):
return True
proc getNewLocation(lastUrl: string, headers: PStringTable): string =
result = headers["Location"]
if result == "": httpError("location header expected")
# Relative URLs. (Not part of the spec, but soon will be.)
let r = parseURL(result)
if r.hostname == "" and r.path != "":
let origParsed = parseURL(lastUrl)
result = origParsed.hostname & "/" & r.path
proc get*(url: string, extraHeaders = "", maxRedirects = 5,
sslContext: PSSLContext = defaultSSLContext,
timeout = -1, userAgent = defUserAgent): TResponse =
## | GETs the ``url`` and returns a ``TResponse`` object
## | This proc also handles redirection
## | Extra headers can be specified and must be separated by ``\c\L``.
## | An optional timeout can be specified in miliseconds, if reading from the
## server takes longer than specified an ETimeout exception will be raised.
result = request(url, httpGET, extraHeaders, "", sslContext, timeout, userAgent)
var lastURL = url
for i in 1..maxRedirects:
if result.status.redirection():
let redirectTo = getNewLocation(lastURL, result.headers)
result = request(redirectTo, httpGET, extraHeaders, "", sslContext,
timeout, userAgent)
lastUrl = redirectTo
proc getContent*(url: string, extraHeaders = "", maxRedirects = 5,
sslContext: PSSLContext = defaultSSLContext,
timeout = -1, userAgent = defUserAgent): string =
## | GETs the body and returns it as a string.
## | Raises exceptions for the status codes ``4xx`` and ``5xx``
## | Extra headers can be specified and must be separated by ``\c\L``.
## | An optional timeout can be specified in miliseconds, if reading from the
## server takes longer than specified an ETimeout exception will be raised.
var r = get(url, extraHeaders, maxRedirects, sslContext, timeout, userAgent)
if r.status[0] in {'4','5'}:
raise newException(EHTTPRequestErr, r.status)
else:
return r.body
proc post*(url: string, extraHeaders = "", body = "",
maxRedirects = 5,
sslContext: PSSLContext = defaultSSLContext,
timeout = -1, userAgent = defUserAgent): TResponse =
## | POSTs ``body`` to the ``url`` and returns a ``TResponse`` object.
## | This proc adds the necessary Content-Length header.
## | This proc also handles redirection.
## | Extra headers can be specified and must be separated by ``\c\L``.
## | An optional timeout can be specified in miliseconds, if reading from the
## server takes longer than specified an ETimeout exception will be raised.
var xh = extraHeaders & "Content-Length: " & $len(body) & "\c\L"
result = request(url, httpPOST, xh, body, sslContext, timeout, userAgent)
var lastUrl = ""
for i in 1..maxRedirects:
if result.status.redirection():
let redirectTo = getNewLocation(lastURL, result.headers)
var meth = if result.status != "307": httpGet else: httpPost
result = request(redirectTo, meth, xh, body, sslContext, timeout,
userAgent)
lastUrl = redirectTo
proc postContent*(url: string, extraHeaders = "", body = "",
maxRedirects = 5,
sslContext: PSSLContext = defaultSSLContext,
timeout = -1, userAgent = defUserAgent): string =
## | POSTs ``body`` to ``url`` and returns the response's body as a string
## | Raises exceptions for the status codes ``4xx`` and ``5xx``
## | Extra headers can be specified and must be separated by ``\c\L``.
## | An optional timeout can be specified in miliseconds, if reading from the
## server takes longer than specified an ETimeout exception will be raised.
var r = post(url, extraHeaders, body, maxRedirects, sslContext, timeout,
userAgent)
if r.status[0] in {'4','5'}:
raise newException(EHTTPRequestErr, r.status)
else:
return r.body
proc downloadFile*(url: string, outputFilename: string,
sslContext: PSSLContext = defaultSSLContext,
timeout = -1, userAgent = defUserAgent) =
## | Downloads ``url`` and saves it to ``outputFilename``
## | An optional timeout can be specified in miliseconds, if reading from the
## server takes longer than specified an ETimeout exception will be raised.
var f: TFile
if open(f, outputFilename, fmWrite):
f.write(getContent(url, sslContext = sslContext, timeout = timeout,
userAgent = userAgent))
f.close()
else:
fileError("Unable to open file")
when isMainModule:
#downloadFile("http://force7.de/nimrod/index.html", "nimrodindex.html")
#downloadFile("http://www.httpwatch.com/", "ChunkTest.html")
#downloadFile("http://validator.w3.org/check?uri=http%3A%2F%2Fgoogle.com",
# "validator.html")
#var r = get("http://validator.w3.org/check?uri=http%3A%2F%2Fgoogle.com&
# charset=%28detect+automatically%29&doctype=Inline&group=0")
var headers: string = "Content-Type: multipart/form-data; boundary=xyz\c\L"
var body: string = "--xyz\c\L"
# soap 1.2 output
body.add("Content-Disposition: form-data; name=\"output\"\c\L")
body.add("\c\Lsoap12\c\L")
# html
body.add("--xyz\c\L")
body.add("Content-Disposition: form-data; name=\"uploaded_file\";" &
" filename=\"test.html\"\c\L")
body.add("Content-Type: text/html\c\L")
body.add("\c\L<html><head></head><body><p>test</p></body></html>\c\L")
body.add("--xyz--")
echo(postContent("http://validator.w3.org/check", headers, body))