Jack,
I'm not sure where N8han (the author of Databinder) hangs out, but it's not
on the Lift list. :-(
Sorry.
David
On Tue, Sep 8, 2009 at 8:58 AM, jack <jack.wid...@gmail.com> wrote:
>
> Please forgive me for including so much code but I have an important
> demo fast approaching and I'm kind of in a bind. I am using
> Databinders Dispatch http library which is a wrapper around Javas
> HttpClient library. I have included the Http class below. Does anyone
> see how to set the user-agent header. Once again I apologize and would
> be much obliged for any help.
>
> import collection.Map
> import collection.immutable.{Map => IMap}
> import util.DynamicVariable
> import java.io.
> {InputStream,OutputStream,BufferedInputStream,BufferedOutputStream}
> import java.net.URI
> import java.util.zip.GZIPInputStream
>
> import org.apache.http._
> import org.apache.http.client._
> import org.apache.http.impl.client.{DefaultHttpClient,
> BasicCredentialsProvider}
> import org.apache.http.client.methods._
> import org.apache.http.client.entity.UrlEncodedFormEntity
> import org.apache.http.client.utils.URLEncodedUtils
>
> import org.apache.http.entity.StringEntity
> import org.apache.http.message.BasicNameValuePair
> import org.apache.http.protocol.HTTP.UTF_8
> import org.apache.http.params.{HttpProtocolParams, BasicHttpParams}
> import org.apache.http.util.EntityUtils
> import org.apache.http.auth.{AuthScope, UsernamePasswordCredentials,
> Credentials}
>
> case class StatusCode(code: Int, contents:String)
> extends Exception("Exceptional resoponse code: " + code + "\n" +
> contents)
>
> /** Http access point. Standard instances to be used by a single
> thread. */
> class Http {
> val credentials = new DynamicVariable[Option[(AuthScope,
> Credentials)]](None)
> val client = new ConfiguredHttpClient
>
> def credentialsProvider = new BasicCredentialsProvider {
> override def getCredentials(scope: AuthScope) = null
> }
>
> /** /** Info Logger for this instance, default returns Connfiggy if
> on classpath else console logger. */
> lazy val log: Logger = try {
> new Logger {
> val delegate = net.lag.logging.Logger.get
> def info(msg: String, items: Any*) { delegate.info(msg, items:
> _*) }
> }
> } catch {
> case e: NoClassDefFoundError => new Logger {
> def info(msg: String, items: Any*) {
> println("INF: [console logger] dispatch: " + msg.format(items:
> _*))
> }
> }
> }
> **/
> /** Execute method for the given host, with logging. */
> def execute(host: HttpHost, req: HttpUriRequest) = {
> //log.info("%s %s%s", req.getMethod, host, req.getURI)
> client.execute(host, req)
> }
> /** Execute for given optional parametrs, with logging. Creates
> local scope for credentials. */
> val execute: (Option[HttpHost], Option[Credentials], HttpUriRequest)
> => HttpResponse = {
> case (Some(host), Some(creds), req) =>
> client.credentials.withValue(Some((new AuthScope
> (host.getHostName, host.getPort), creds)))(execute(host, req))
> case (None, Some(creds), _) => error("Credentials specified
> without explicit host")
> case (Some(host), _, req) => execute(host, req)
> case (_, _, req) =>
> //log.info("%s %s", req.getMethod, req.getURI)
> client.execute(req)
> }
> /** Execute full request-response handler. */
> def x[T](hand: Handler[T]): T = x(hand.request)(hand.block)
> /** Execute request and handle response codes, response, and entity
> in block */
> def x [T](req: Request)(block: Handler.F[T]) = {
> val res = execute(req.host, req.creds, req.req)
> val ent = res.getEntity match {
> case null => None
> case ent => Some(ent)
> }
> try { block(res.getStatusLine.getStatusCode, res, ent) }
> finally { ent foreach (_.consumeContent) }
> }
> /** Apply Response Handler if reponse code returns true from chk. */
> def when[T](chk: Int => Boolean)(hand: Handler[T]) = x(hand.request)
> {
> case (code, res, ent) if chk(code) => hand.block(code, res, ent)
> case (code, _, Some(ent)) => throw StatusCode(code,
> EntityUtils.toString(ent, UTF_8))
> case (code, _, _) => throw StatusCode(code, "[no entity]")
> }
> /** Apply a custom block in addition to predefined response Handler.
> */
> def also[A,B](hand: Handler[B])(block: Handler.F[A]) =
> x(hand.request) { (code, res, ent) => ( hand.block(code, res,
> ent), block(code, res, ent) ) }
>
> /** Apply handler block when response code is 200 - 204 */
> def apply[T](hand: Handler[T]) = (this when {code => (200 to 204)
> contains code})(hand)
> }
>
> /** Nil request, useful to kick off a descriptors that don't have a
> factory. */
> object /\ extends Request(None, None, Nil)
>
> /* Factory for requests from a host */
> object :/ {
> def apply(hostname: String, port: Int): Request =
> new Request(Some(new HttpHost(hostname, port)), None, Nil)
>
> def apply(hostname: String): Request = new Request(Some(new HttpHost
> (hostname)), None, Nil)
> }
>
> /** Factory for requests from a directory, prepends '/'. */
> object / {
> def apply(path: String) = /\ / path
> }
>
> object Request {
> /** Request transformer */
> type Xf = HttpRequestBase => HttpRequestBase
> /** Updates the request URI with the given string-to-string
> function. (mutates request) */
> def uri_xf(sxf: String => String)(req: HttpRequestBase) = {
> req.setURI(URI.create(sxf(req.getURI.toString)))
> req
> }
> }
>
> /** Request handler, contains request descriptor and a function to
> transform the result. */
> case class Handler[T](request: Request, block: Handler.F[T]) extends
> Handlers {
> /** Create a new handler with block that receives all response
> parameters and
> this handler's block converted to parameterless function. */
> def apply[R](next: (Int, HttpResponse, Option[HttpEntity], () => T)
> => R) =
> new Handler(request, {(code, res, ent) =>
> next(code, res, ent, () => block(code, res, ent))
> })
> }
>
> object Handler {
> type F[T] = (Int, HttpResponse, Option[HttpEntity]) => T
> /** Turns a simple entity handler in into a full response handler
> that fails if no entity */
> def apply[T](req: Request, block: HttpEntity => T): Handler[T] =
> Handler(req, { (code, res, ent) => ent match {
> case Some(ent) => block(ent)
> case None => error("response has no entity: " + res)
> } } )
> }
>
> class Post(val values: Map[String, Any]) extends HttpPost {
> this setEntity new UrlEncodedFormEntity(Http.map2ee(values), UTF_8)
> }
>
> /** Request descriptor, possibly contains a host, credentials, and a
> list of transformation functions. */
> class Request(val host: Option[HttpHost], val creds: Option
> [Credentials], val xfs: List[Request.Xf]) extends Handlers {
>
> /** Construct with path or full URI. */
> def this(str: String) = this(None, None, Request.uri_xf(cur => cur +
> str)_ :: Nil)
>
> /** Construct as a clone, e.g. in class extends clause. */
> def this(req: Request) = this(req.host, req.creds, req.xfs)
>
> def next(xf: Request.Xf) = new Request(host, creds, xf :: xfs)
> def next_uri(sxf: String => String) = next(Request.uri_xf(sxf))
>
> def mimic(dest: HttpRequestBase)(req: HttpRequestBase) = {
> dest.setURI(req.getURI)
> dest.setHeaders(req.getAllHeaders)
> dest
> }
>
> // The below functions create new request descriptors based off of
> the current one.
> // Most are intended to be used as infix operators; those that don't
> take a parameter
> // have character names to be used with dot notation, e.g. /:
> ("example.com").HEAD.secure >>> {...}
>
> /** Set credentials to be used for this request; requires a host
> value :/(...) upon execution. */
> def as (name: String, pass: String) =
> new Request(host, Some(new UsernamePasswordCredentials(name,
> pass)), xfs)
>
> /** Convert this to a secure (scheme https) request if not already
> */
> def secure = new Request(host map {
> h => new HttpHost(h.getHostName, h.getPort, "https") // default
> port -1 works for either
> } orElse { error("secure requires an explicit host") }, creds, xfs)
>
> /** Combine this request with another. */
> def <& (req: Request) = new Request(host orElse req.host, creds
> orElse req.creds, req.xfs ::: xfs)
>
> /** Combine this request with another handler. */
> def >& [T] (other: Handler[T]) = new Handler(this <& other.request,
> other.block)
>
> /** Append an element to this request's path, joins with '/'.
> (mutates request) */
> def / (path: String) = next_uri { _ + "/" + path }
>
> /** Add headers to this request. (mutates request) */
> def <:< (values: Map[String, String]) = next { req =>
> values foreach { case (k, v) => req.addHeader(k, v) }
> req
> }
>
> /* Add a gzip acceptance header */
> def gzip = this <:< IMap("Accept-Encoding" -> "gzip")
>
> /** Put the given object.toString and return response wrapper. (new
> request, mimics) */
> def <<< (body: Any) = next {
> val m = new HttpPut
> m setEntity new StringEntity(body.toString, UTF_8)
> HttpProtocolParams.setUseExpectContinue(m.getParams, false)
> mimic(m)_
> }
> /** Post the given key value sequence and return response wrapper.
> (new request, mimics) */
> def << (values: Map[String, Any]) = next { mimic(new Post(values))
> _ }
>
> /** Add query parameters. (mutates request) */
> def <<? (values: Map[String, Any]) = next_uri { uri =>
> if (values.isEmpty) uri
> else uri + (
> if (uri contains '?') '&' + Http.q_str(values) else (Http ?
> values)
> )
> }
>
> // generators that change request method without adding parameters
>
> /** HTTP post request. (new request, mimics) */
> def POST = next { mimic(new Post(IMap.empty))_ }
>
> /** HTTP delete request. (new request, mimics) */
> def DELETE = next { mimic(new HttpDelete)_ }
>
> /** HTTP head request. (new request, mimics). See >:> to access
> headers. */
> def HEAD = next { mimic(new HttpHead)_ }
>
> // end Request generators
>
> /** Builds underlying request starting with a blank get and applying
> transformers right to left. */
> lazy val req = {
> val start: HttpRequestBase = new HttpGet("")
> (xfs :\ start) { (a,b) => a(b) }
> }
>
> /** @return URI based on this request, e.g. if needed outside
> Disptach. */
> def to_uri = Http.to_uri(host, req)
>
> /** Use this request for trait Handlers */
> val request = this
> }
> trait Handlers {
> /** the below functions produce Handlers based on this request
> descriptor */
> val request: Request
>
> /** Handle InputStream in block, handle gzip if so encoded. */
> def >> [T] (block: InputStream => T) = Handler(request, { ent =>
> block (
> if(ent.getContentEncoding != null &&
> ent.getContentEncoding.getValue == "gzip")
> new GZIPInputStream(ent.getContent)
> else ent.getContent
> ) } )
> /** Handle some non-huge response body as a String, in a block. */
> def >- [T] (block: String => T) = >> { stm => block
> (scala.io.Source.fromInputStream(stm).mkString) }
> /** Return some non-huge response as a String. */
> def as_str = >- { s => s }
> /** Write to the given OutputStream. */
> def >>> [OS <: OutputStream](out: OS) = Handler(request, { ent =>
> ent.writeTo(out); out })
> /** Process response as XML document in block */
> def <> [T] (block: xml.Elem => T) = >> { stm => block(xml.XML.load
> (stm)) }
>
> /** Process header as Map in block. Map returns empty set for header
> name misses. */
> def >:> [T] (block: IMap[String, Set[String]] => T) =
> Handler(request, (_, res, _) =>
> block((IMap[String, Set[String]]().withDefaultValue(Set()) /:
> res.getAllHeaders) {
> (m, h) => m + (h.getName -> (m(h.getName) + h.getValue))
> } )
> )
>
> /** Ignore response body. */
> def >| = Handler(request, (code, res, ent) => ())
>
> /** Split into two request handlers, return results of each in
> tuple. */
> def >+ [A, B] (block: Handlers => (Handler[A], Handler[B])) = {
> new Handler[(A,B)] ( request, { (code, res, opt_ent) =>
> val (a, b) = block(new Handlers { val request = /\ })
> (a.block(code, res, opt_ent), b.block(code,res,opt_ent))
> } )
> }
> }
>
> /** Basic extension of DefaultHttpClient defaulting to Http 1.1, UTF8,
> and no Expect-Continue.
> Scopes authorization credentials to particular requests thorugh a
> DynamicVariable. */
> class ConfiguredHttpClient extends DefaultHttpClient {
> override def createHttpParams = {
> val params = new BasicHttpParams
> HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1)
> HttpProtocolParams.setContentCharset(params, UTF_8)
> HttpProtocolParams.setUseExpectContinue(params, false)
> params
> }
> val credentials = new DynamicVariable[Option[(AuthScope,
> Credentials)]](None)
> setCredentialsProvider(new BasicCredentialsProvider {
> override def getCredentials(scope: AuthScope) = credentials.value
> match {
> case Some((auth_scope, creds)) if scope.`match`(auth_scope) >= 0
> => creds
> case _ => null
> }
> })
> }
>
> /** Used by client APIs to build Handler or other objects via
> chaining, completed implicitly.
> * @see Http#builder2product */
> trait Builder[T] { def product:T }
>
> /** May be used directly from any thread. */
> object Http extends Http {
> import org.apache.http.conn.scheme.
> {Scheme,SchemeRegistry,PlainSocketFactory}
> import org.apache.http.conn.ssl.SSLSocketFactory
> import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager
>
> /** import to support e.g. Http("http://example.com/"; >>>
> System.out) */
> implicit def str2req(str: String) = new Request(str)
>
> implicit def builder2product[T](builder: Builder[T]) =
> builder.product
>
> override val client = new ConfiguredHttpClient {
> override def createClientConnectionManager() = {
> val registry = new SchemeRegistry()
> registry.register(new Scheme("http",
> PlainSocketFactory.getSocketFactory(), 80))
> registry.register(new Scheme("https",
> SSLSocketFactory.getSocketFactory(), 443))
> new ThreadSafeClientConnManager(getParams(), registry)
> }
> }
> /** Shutdown connection manager, threads. (Needed to close console
> cleanly.) */
> def shutdown() = client.getConnectionManager.shutdown()
>
> /** Convert repeating name value tuples to list of pairs for
> httpclient */
> def map2ee(values: Map[String, Any]) = java.util.Arrays asList (
> values.toSeq map { case (k, v) => new BasicNameValuePair(k,
> v.toString) } toArray : _*
> )
> /** @return %-encoded string for use in URLs */
> def % (s: String) = java.net.URLEncoder.encode(s, UTF_8)
>
> /** @return %-decoded string e.g. from query string or form body */
> def -% (s: String) = java.net.URLDecoder.decode(s, UTF_8)
>
> /** @return formatted and %-encoded query string, e.g.
> name=value&name2=value2 */
> def q_str (values: Map[String, Any]) = URLEncodedUtils.format(map2ee
> (values), UTF_8)
>
> /** @return formatted query string prepended by ? unless values map
> is empty */
> def ? (values: Map[String, Any]) = if (values.isEmpty) "" else "?" +
> q_str(values)
>
> /** @return URI built from HttpHost if present combined with a
> HttpClient request object. */
> def to_uri(host: Option[HttpHost], req: HttpRequestBase) =
> URI.create(host.map(_.toURI).getOrElse("")).resolve(req.getURI)
> }
>
> >
>
--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp
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