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#
#
# 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))
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
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 charAt(d: var string, i: var int, s: TSocket): char {.inline.} =
result = d[i]
while result == '\0':
d = s.recv()
i = 0
result = d[i]
proc parseChunks(d: var string, start: int, s: TSocket): string =
# get chunks:
var i = start
result = ""
while true:
var chunkSize = 0
var digitFound = false
while true:
case d[i]
of '0'..'9':
digitFound = true
chunkSize = chunkSize shl 4 or (ord(d[i]) - ord('0'))
of 'a'..'f':
digitFound = true
chunkSize = chunkSize shl 4 or (ord(d[i]) - ord('a') + 10)
of 'A'..'F':
digitFound = true
chunkSize = chunkSize shl 4 or (ord(d[i]) - ord('A') + 10)
of '\0':
d = s.recv()
i = -1
else: break
inc(i)
if not digitFound: httpError("Chunksize expected")
if chunkSize <= 0: break
while charAt(d, i, s) notin {'\C', '\L', '\0'}: inc(i)
if charAt(d, i, s) == '\C': inc(i)
if charAt(d, i, s) == '\L': inc(i)
else: httpError("CR-LF after chunksize expected")
var x = substr(d, i, i+chunkSize-1)
var size = x.len
result.add(x)
inc(i, size)
if size < chunkSize:
# read in the rest:
var missing = chunkSize - size
var L = result.len
setLen(result, L + missing)
while missing > 0:
var bytesRead = s.recv(addr(result[L]), missing)
inc(L, bytesRead)
dec(missing, bytesRead)
# next chunk:
d = s.recv()
i = 0
# skip trailing CR-LF:
while charAt(d, i, s) in {'\C', '\L'}: inc(i)
proc parseBody(d: var string, start: int, s: TSocket,
headers: PStringTable): string =
if headers["Transfer-Encoding"] == "chunked":
result = parseChunks(d, start, s)
else:
result = substr(d, start)
# -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()
while result.len() < length: result.add(s.recv())
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":
while True:
var moreData = recv(s)
if moreData.len == 0: break
result.add(moreData)
proc parseResponse(s: TSocket): TResponse =
var d = s.recv()
var i = 0
# Parse the version
# Parses the first line of the headers
# ``HTTP/1.1`` 200 OK
var L = skipIgnoreCase(d, "HTTP/1.1", i)
if L > 0:
result.version = "1.1"
inc(i, L)
else:
L = skipIgnoreCase(d, "HTTP/1.0", i)
if L > 0:
result.version = "1.0"
inc(i, L)
else:
httpError("invalid HTTP header")
L = skipWhiteSpace(d, i)
if L <= 0: httpError("invalid HTTP header")
inc(i, L)
result.status = ""
while d[i] notin {'\C', '\L', '\0'}:
result.status.add(d[i])
inc(i)
if d[i] == '\C': inc(i)
if d[i] == '\L': inc(i)
else: httpError("invalid HTTP header, CR-LF expected")
# Parse the headers
# Everything after the first line leading up to the body
# htype: hvalue
result.headers = newStringTable(modeCaseInsensitive)
while true:
var key = ""
while d[i] != ':':
if d[i] == '\0': httpError("invalid HTTP header, ':' expected")
key.add(d[i])
inc(i)
inc(i) # skip ':'
if d[i] == ' ': inc(i) # skip if the character is a space
var val = ""
while d[i] notin {'\C', '\L', '\0'}:
val.add(d[i])
inc(i)
result.headers[key] = val
if d[i] == '\C': inc(i)
if d[i] == '\L': inc(i)
else: httpError("invalid HTTP header, CR-LF expected")
if d[i] == '\C': inc(i)
if d[i] == '\L':
inc(i)
break
result.body = parseBody(d, i, s, result.headers)
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.
proc request*(url: string, httpMethod = httpGET, extraHeaders = "",
body = ""): TResponse =
## | Requests ``url`` with the specified ``httpMethod``.
## | Extra headers can be specified and must be seperated by ``\c\L``
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")
add(headers, extraHeaders)
add(headers, "\c\L")
var s = socket()
s.connect(r.hostname, TPort(80))
s.send(headers)
if body != "":
s.send(body)
result = parseResponse(s)
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 get*(url: string, maxRedirects = 5): TResponse =
## | GET's the ``url`` and returns a ``TResponse`` object
## | This proc also handles redirection
result = request(url)
for i in 1..maxRedirects:
if result.status.redirection():
var locationHeader = result.headers["Location"]
if locationHeader == "": httpError("location header expected")
result = request(locationHeader)
proc getContent*(url: string): string =
## | GET's the body and returns it as a string.
## | Raises exceptions for the status codes ``4xx`` and ``5xx``
var r = get(url)
if r.status[0] in {'4','5'}:
raise newException(EHTTPRequestErr, r.status)
else:
return r.body
proc post*(url: string, extraHeaders = "", body = "",
maxRedirects = 5): TResponse =
## | POST's ``body`` to the ``url`` and returns a ``TResponse`` object.
## | This proc adds the necessary Content-Length header.
## | This proc also handles redirection.
var xh = extraHeaders & "Content-Length: " & $len(body) & "\c\L"
result = request(url, httpPOST, xh, body)
for i in 1..maxRedirects:
if result.status.redirection():
var locationHeader = result.headers["Location"]
if locationHeader == "": httpError("location header expected")
var meth = if result.status != "307": httpGet else: httpPost
result = request(locationHeader, meth, xh, body)
proc postContent*(url: string, extraHeaders = "", body = ""): string =
## | POST's ``body`` to ``url`` and returns the response's body as a string
## | Raises exceptions for the status codes ``4xx`` and ``5xx``
var r = post(url, extraHeaders, body)
if r.status[0] in {'4','5'}:
raise newException(EHTTPRequestErr, r.status)
else:
return r.body
proc downloadFile*(url: string, outputFilename: string) =
## Downloads ``url`` and saves it to ``outputFilename``
var f: TFile
if open(f, outputFilename, fmWrite):
f.write(getContent(url))
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))
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