# std/httpclient

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This module implements a simple HTTP client that can be used to retrieve webpages and other data.

# Retrieving a website

This example uses HTTP GET to retrieve `http://google.com`:

    import std/httpclient
    var client = newHttpClient()
    echo client.getContent("http://google.com")

The same action can also be performed asynchronously, simply use the `AsyncHttpClient`:

    import std/[asyncdispatch, httpclient]

    proc asyncProc(): Future[string] {.async.} =
      var client = newAsyncHttpClient()
      return await client.getContent("http://example.com")

    echo waitFor asyncProc()

The functionality implemented by `HttpClient` and `AsyncHttpClient` is the same, so you can use whichever one suits you best in the examples shown here.

Note: You need to run asynchronous examples in an async proc otherwise you will get an `Undeclared identifier: 'await'` error.

# 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 be validated to the server.

    var client = newHttpClient()
    var data = newMultipartData()
    data["output"] = "soap12"
    data["uploaded_file"] = ("test.html", "text/html",
      "<html><head></head><body><p>test</p></body></html>")

    echo client.postContent("http://validator.w3.org/check", multipart=data)

To stream files from disk when performing the request, use `addFiles`.

Note: This will allocate a new `Mimetypes` database every time you call it, you can pass your own via the `mimeDb` parameter to avoid this.

    let mimes = newMimetypes()
    var client = newHttpClient()
    var data = newMultipartData()
    data.addFiles({"uploaded_file": "test.html"}, mimeDb = mimes)

    echo client.postContent("http://validator.w3.org/check", multipart=data)

You can also make post requests with custom headers. This example sets `Content-Type` to `application/json` and uses a json object for the body

    import std/[httpclient, json]

    let client = newHttpClient()
    client.headers = newHttpHeaders({ "Content-Type": "application/json" })
    let body = %*{
        "data": "some text"
    }
    let response = client.request("http://some.api", httpMethod = HttpPost, body = $body)
    echo response.status

# Progress reporting

You may specify a callback procedure to be called during an HTTP request. This callback will be executed every second with information about the progress of the HTTP request.

    import std/[asyncdispatch, httpclient]

    proc onProgressChanged(total, progress, speed: BiggestInt) {.async.} =
      echo("Downloaded ", progress, " of ", total)
      echo("Current rate: ", speed div 1000, "kb/s")

    proc asyncProc() {.async.} =
      var client = newAsyncHttpClient()
      client.onProgressChanged = onProgressChanged
      discard await client.getContent("http://speedtest-ams2.digitalocean.com/100mb.test")

    waitFor asyncProc()

If you would like to remove the callback simply set it to `nil`.

    client.onProgressChanged = nil

Warning: The `total` reported by httpclient may be 0 in some cases.

# 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 will also have to compile with `ssl` defined like so: `nim c -d:ssl ...`.

Certificate validation is performed by default.

A set of directories and files from the ssl_certs module are scanned to locate CA certificates.

Example of setting SSL verification parameters in a new client:

    import httpclient
    var client = newHttpClient(sslContext=newContext(verifyMode=CVerifyPeer))

There are three options for verify mode:

- `CVerifyNone`: certificates are not verified;
- `CVerifyPeer`: certificates are verified;
- `CVerifyPeerUseEnvVars`: certificates are verified and the optional environment variables SSL_CERT_FILE and SSL_CERT_DIR are also used to locate certificates

See newContext to tweak or disable certificate validation.

# Timeouts

Currently only the synchronous functions support a timeout. The timeout is measured in milliseconds, once it is set any call on a socket which may block will be susceptible to this timeout.

It may be surprising but 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 the client within the specified timeout a `TimeoutError` exception will be raised.

Here is how to set a timeout when creating an `HttpClient` instance:

    import std/httpclient

    let client = newHttpClient(timeout = 42)

# Proxy

A proxy can be specified as a param to any of the procedures defined in this module. To do this, use the `newProxy` constructor. Unfortunately, only basic authentication is supported at the moment.

Some examples on how to configure a Proxy for `HttpClient`:

    import std/httpclient

    let myProxy = newProxy("http://myproxy.network")
    let client = newHttpClient(proxy = myProxy)

Get Proxy URL from environment variables:

    import std/httpclient

    var url = ""
    try:
      if existsEnv("http_proxy"):
        url = getEnv("http_proxy")
      elif existsEnv("https_proxy"):
        url = getEnv("https_proxy")
    except ValueError:
      echo "Unable to parse proxy from environment variables."

    let myProxy = newProxy(url = url)
    let client = newHttpClient(proxy = myProxy)

# Redirects

The maximum redirects can be set with the `maxRedirects` of `int` type, it specifies the maximum amount of redirects to follow, it defaults to `5`, you can set it to `0` to disable redirects.

Here you can see an example about how to set the `maxRedirects` of `HttpClient`:

    import std/httpclient

    let client = newHttpClient(maxRedirects = 0)

# Imports

since, net, strutils, uri, parseutils, base64, os, mimetypes, math, random, httpcore, times, tables, streams, monotimes, asyncnet, asyncdispatch, asyncfile, nativesockets

# Types

    AsyncHttpClient = HttpClientBase[AsyncSocket]

  Source Edit

    AsyncResponse = ref object
      version*: string
      status*: string
      headers*: HttpHeaders
      body: string
      bodyStream*: FutureStream[string]

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    HttpClient = HttpClientBase[Socket]

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    HttpClientBase[SocketType] = ref object
      socket: SocketType
      connected: bool
      currentURL: Uri            ## Where we are currently connected.
      headers*: HttpHeaders      ## Headers to send in requests.
      maxRedirects: Natural      ## Maximum redirects, set to `0` to disable.
      userAgent: string
      timeout*: int              ## Only used for blocking HttpClient for now.
      proxy: Proxy               ## `nil` or the callback to call when request progress changes.
      when SocketType is Socket:
        onProgressChanged
      else:
        onProgressChanged
      when false:
        sslContext
      contentTotal: BiggestInt
      contentProgress: BiggestInt
      oneSecondProgress: BiggestInt
      lastProgressReport: MonoTime
      when SocketType is AsyncSocket:
          bodyStream
          parseBodyFut

      else:
        bodyStream
      getBody: bool              ## When `false`, the body is never read in requestAux.

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    HttpRequestError = object of IOError

  Thrown in the `getContent` proc and `postContent` proc, when the server returns an error Source Edit

    MultipartData = ref object
      content: seq[MultipartEntry]

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    MultipartEntries = openArray[tuple[name, content: string]]

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    ProgressChangedProc[ReturnType] = proc (total, progress, speed: BiggestInt): ReturnType {.
        closure, ...gcsafe.}

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    ProtocolError = object of IOError

  exception that is raised when server does not conform to the implemented protocol Source Edit

    Proxy = ref object
      url*: Uri
      auth*: string

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    Response = ref object
      version*: string
      status*: string
      headers*: HttpHeaders
      body: string
      bodyStream*: Stream

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# Consts

    defUserAgent = "Nim httpclient/1.6.8"

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# Procs

    proc `$`(data: MultipartData): string {....raises: [], tags: [].}

  convert MultipartData to string so it's human readable when echo see https://github.com/nim-lang/Nim/issues/11863 Source Edit

    proc `[]=`(p: MultipartData; name, content: string) {.inline,
        ...raises: [ValueError], tags: [].}

  Add a multipart entry to the multipart data `p`. The value is added without a filename and without a content type.

      data["username"] = "NimUser"

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    proc `[]=`(p: MultipartData; name: string;
               file: tuple[name, contentType, content: string]) {.inline,
        ...raises: [ValueError], tags: [].}

  Add a file to the multipart data `p`, specifying filename, contentType and content manually.

      data["uploaded_file"] = ("test.html", "text/html",
        "<html><head></head><body><p>test</p></body></html>")

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    proc add(p: MultipartData; name, content: string; filename: string = "";
             contentType: string = ""; useStream = true) {....raises: [ValueError],
        tags: [].}

  Add a value to the multipart data.

  When `useStream` is `false`, the file will be read into memory.

  Raises a `ValueError` exception if `name`, `filename` or `contentType` contain newline characters.

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    proc add(p: MultipartData; xs: MultipartEntries): MultipartData {.discardable,
        ...raises: [ValueError], tags: [].}

  Add a list of multipart entries to the multipart data `p`. All values are added without a filename and without a content type.

      data.add({"action": "login", "format": "json"})

  Source Edit

    proc addFiles(p: MultipartData; xs: openArray[tuple[name, file: string]];
                  mimeDb = newMimetypes(); useStream = true): MultipartData {.
        discardable, ...raises: [IOError, ValueError], tags: [ReadIOEffect].}

  Add files to a multipart data object. The files will be streamed from disk when the request is being made. When `stream` is `false`, the files are instead read into memory, but beware this is very memory ineffecient even for small files. The MIME types will automatically be determined. Raises an `IOError` if the file cannot be opened or reading fails. To manually specify file content, filename and MIME type, use `[]=` instead.

      data.addFiles({"uploaded_file": "public/test.html"})

  Source Edit

    proc body(response: AsyncResponse): Future[string] {.
        ...raises: [Exception, ValueError], tags: [RootEffect].}

  Reads the response's body and caches it. The read is performed only once. Source Edit

    proc body(response: Response): string {....raises: [IOError, OSError],
                                            tags: [ReadIOEffect].}

  Retrieves the specified response's body.

  The response's body stream is read synchronously.

  Source Edit

    proc close(client: HttpClient | AsyncHttpClient)

  Closes any connections held by the HTTP client. Source Edit

    proc code(response: Response | AsyncResponse): HttpCode {.
        ...raises: [ValueError, OverflowDefect].}

  Retrieves the specified response's `HttpCode`.

  Raises a `ValueError` if the response's `status` does not have a corresponding `HttpCode`.

  Source Edit

    proc contentLength(response: Response | AsyncResponse): int

  Retrieves the specified response's content length.

  This is effectively the value of the "Content-Length" header.

  A `ValueError` exception will be raised if the value is not an integer.

  Source Edit

    proc contentType(response: Response | AsyncResponse): string {.inline.}

  Retrieves the specified response's content type.

  This is effectively the value of the "Content-Type" header.

  Source Edit

    proc delete(client: AsyncHttpClient; url: Uri | string): Future[AsyncResponse]

  Connects to the hostname specified by the URL and performs a DELETE request. This procedure uses httpClient values such as `client.maxRedirects`. Source Edit

    proc delete(client: HttpClient; url: Uri | string): Response

  Source Edit

    proc deleteContent(client: AsyncHttpClient; url: Uri | string): Future[string]

  Connects to the hostname specified by the URL and returns the content of a DELETE request. Source Edit

    proc deleteContent(client: HttpClient; url: Uri | string): string

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    proc downloadFile(client: AsyncHttpClient; url: Uri | string; filename: string): Future[
        void]

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    proc downloadFile(client: HttpClient; url: Uri | string; filename: string)

  Downloads `url` and saves it to `filename`. Source Edit

    proc get(client: AsyncHttpClient; url: Uri | string): Future[AsyncResponse]

  Connects to the hostname specified by the URL and performs a GET request.

  This procedure uses httpClient values such as `client.maxRedirects`.

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    proc get(client: HttpClient; url: Uri | string): Response

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    proc getContent(client: AsyncHttpClient; url: Uri | string): Future[string]

  Connects to the hostname specified by the URL and returns the content of a GET request. Source Edit

    proc getContent(client: HttpClient; url: Uri | string): string

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    proc getSocket(client: AsyncHttpClient): AsyncSocket {.inline, ...raises: [],
        tags: [].}

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    proc getSocket(client: HttpClient): Socket {.inline, ...raises: [], tags: [].}

  Get network socket, useful if you want to find out more details about the connection

  this example shows info about local and remote endpoints

      if client.connected:
        echo client.getSocket.getLocalAddr
        echo client.getSocket.getPeerAddr

  Source Edit

    proc head(client: AsyncHttpClient; url: Uri | string): Future[AsyncResponse]

  Connects to the hostname specified by the URL and performs a HEAD request.

  This procedure uses httpClient values such as `client.maxRedirects`.

  Source Edit

    proc head(client: HttpClient; url: Uri | string): Response

  Source Edit

    proc lastModified(response: Response | AsyncResponse): DateTime

  Retrieves the specified response's last modified time.

  This is effectively the value of the "Last-Modified" header.

  Raises a `ValueError` if the parsing fails or the value is not a correctly formatted time.

  Source Edit

    proc newAsyncHttpClient(userAgent = defUserAgent; maxRedirects = 5;
                            sslContext = getDefaultSSL(); proxy: Proxy = nil;
                            headers = newHttpHeaders()): AsyncHttpClient {.
        ...raises: [], tags: [].}

  Creates a new AsyncHttpClient instance.

  `userAgent` specifies the user agent that will be used when making requests.

  `maxRedirects` specifies the maximum amount of redirects to follow, default is 5.

  `sslContext` specifies the SSL context to use for HTTPS requests.

  `proxy` specifies an HTTP proxy to use for this HTTP client's connections.

  `headers` specifies the HTTP Headers.

  Example:

      import std/[asyncdispatch, strutils]

      proc asyncProc(): Future[string] {.async.} =
        let client = newAsyncHttpClient()
        result = await client.getContent("http://example.com")

      let exampleHtml = waitFor asyncProc()
      assert "Example Domain" in exampleHtml
      assert "Pizza" notin exampleHtml

  Source Edit

    proc newHttpClient(userAgent = defUserAgent; maxRedirects = 5;
                       sslContext = getDefaultSSL(); proxy: Proxy = nil;
                       timeout = -1; headers = newHttpHeaders()): HttpClient {.
        ...raises: [], tags: [].}

  Creates a new HttpClient instance.

  `userAgent` specifies the user agent that will be used when making requests.

  `maxRedirects` specifies the maximum amount of redirects to follow, default is 5.

  `sslContext` specifies the SSL context to use for HTTPS requests. See SSL/TLS support

  `proxy` specifies an HTTP proxy to use for this HTTP client's connections.

  `timeout` specifies the number of milliseconds to allow before a `TimeoutError` is raised.

  `headers` specifies the HTTP Headers.

  Example:

      import std/strutils

      let exampleHtml = newHttpClient().getContent("http://example.com")
      assert "Example Domain" in exampleHtml
      assert "Pizza" notin exampleHtml

  Source Edit

    proc newMultipartData(): MultipartData {.inline, ...raises: [], tags: [].}

  Constructs a new `MultipartData` object. Source Edit

    proc newMultipartData(xs: MultipartEntries): MultipartData {.
        ...raises: [ValueError], tags: [].}

  Create a new multipart data object and fill it with the entries `xs` directly.

      var data = newMultipartData({"action": "login", "format": "json"})

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    proc newProxy(url: string; auth = ""): Proxy {....raises: [], tags: [].}

  Constructs a new `TProxy` object. Source Edit

    proc newProxy(url: Uri; auth = ""): Proxy {....raises: [], tags: [].}

  Constructs a new `TProxy` object. Source Edit

    proc patch(client: AsyncHttpClient; url: Uri | string; body = "";
               multipart: MultipartData = nil): Future[AsyncResponse]

  Connects to the hostname specified by the URL and performs a PATCH request. This procedure uses httpClient values such as `client.maxRedirects`. Source Edit

    proc patch(client: HttpClient; url: Uri | string; body = "";
               multipart: MultipartData = nil): Response

  Source Edit

    proc patchContent(client: AsyncHttpClient; url: Uri | string; body = "";
                      multipart: MultipartData = nil): Future[string]

  Connects to the hostname specified by the URL and returns the content of a PATCH request. Source Edit

    proc patchContent(client: HttpClient; url: Uri | string; body = "";
                      multipart: MultipartData = nil): string

  Source Edit

    proc post(client: AsyncHttpClient; url: Uri | string; body = "";
              multipart: MultipartData = nil): Future[AsyncResponse]

  Connects to the hostname specified by the URL and performs a POST request. This procedure uses httpClient values such as `client.maxRedirects`. Source Edit

    proc post(client: HttpClient; url: Uri | string; body = "";
              multipart: MultipartData = nil): Response

  Source Edit

    proc postContent(client: AsyncHttpClient; url: Uri | string; body = "";
                     multipart: MultipartData = nil): Future[string]

  Connects to the hostname specified by the URL and returns the content of a POST request. Source Edit

    proc postContent(client: HttpClient; url: Uri | string; body = "";
                     multipart: MultipartData = nil): string

  Source Edit

    proc put(client: AsyncHttpClient; url: Uri | string; body = "";
             multipart: MultipartData = nil): Future[AsyncResponse]

  Connects to the hostname specified by the URL and performs a PUT request. This procedure uses httpClient values such as `client.maxRedirects`. Source Edit

    proc put(client: HttpClient; url: Uri | string; body = "";
             multipart: MultipartData = nil): Response

  Source Edit

    proc putContent(client: AsyncHttpClient; url: Uri | string; body = "";
                    multipart: MultipartData = nil): Future[string]

  Connects to the hostname specified by the URL andreturns the content of a PUT request. Source Edit

    proc putContent(client: HttpClient; url: Uri | string; body = "";
                    multipart: MultipartData = nil): string

  Source Edit

    proc request(client: AsyncHttpClient; url: Uri | string;
                 httpMethod: HttpMethod | string = HttpGet; body = "";
                 headers: HttpHeaders = nil; multipart: MultipartData = nil): Future[
        AsyncResponse]

  Connects to the hostname specified by the URL and performs a request using the custom method string specified by `httpMethod`.

  Connection will be kept alive. Further requests on the same `client` to the same hostname will not require a new connection to be made. The connection can be closed by using the `close` procedure.

  This procedure will follow redirects up to a maximum number of redirects specified in `client.maxRedirects`.

  You need to make sure that the `url` doesn't contain any newline characters. Failing to do so will raise `AssertionDefect`.

  `headers` are HTTP headers that override the `client.headers` for this specific request only and will not be persisted.

  Deprecated since v1.5: use HttpMethod enum instead; string parameter httpMethod is deprecated

  Source Edit

    proc request(client: HttpClient; url: Uri | string;
                 httpMethod: HttpMethod | string = HttpGet; body = "";
                 headers: HttpHeaders = nil; multipart: MultipartData = nil): Response

  Source Edit

# Exports

Http417, Http503, Http431, HttpTrace, contains, Http304, Http406, ==, $, HttpMethod, Http408, is4xx, is1xx, Http411, is3xx, Http207, Http418, Http206, HttpHead, HttpPost, clear, Http101, httpNewLine, Http505, Http413, Http423, Http409, hasKey, Http200, []=, Http414, add, Http401, Http511, Http205, ==, Http407, Http500, Http404, Http416, Http507, Http302, HttpHeaders, Http300, Http428, Http410, is2xx, Http202, Http502, headerLimit, HttpHeaderValues, Http425, contains, newHttpHeaders, $, [], Http510, newHttpHeaders, Http305, Http451, Http504, Http426, HttpConnect, ==, Http308, del, HttpPut, Http402, pairs, Http429, HttpVersion, HttpDelete, is5xx, Http421, HttpOptions, Http307, Http102, Http301, HttpPatch, Http201, Http203, getOrDefault, Http100, Http208, Http501, []=, len, Http506, Http400, Http403, HttpGet, Http508, Http415, toString, Http412, Http103, Http405, Http303, Http204, Http424, HttpCode, Http422, Http226, []