[nit.git] / lib / curl / curl.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2013 Matthieu Lucas <lucasmatthieu@gmail.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Data transfer with URL syntax
#
# Download or upload over HTTP with `CurlHTTPRequest` and send emails with `CurlMail`.
module curl

import native_curl

redef class Sys
        # Shared Curl library handle
        #
        # Usually, you do not have to use this attribute, it instancied by `CurlHTTPRequest` and `CurlMail`.
        # But in some cases you may want to finalize it to free some small resources.
        # However, if Curl services are needed once again, this attribute must be manually set.
        var curl: Curl = new Curl is lazy, writable
end

# Curl library handle, it is initialized and released with this class
class Curl
        super FinalizableOnce

        private var native = new NativeCurl.easy_init

        # Check for correct initialization
        fun is_ok: Bool do return self.native.is_init

        redef fun finalize_once do if is_ok then native.easy_clean
end

# CURL Request
class CurlRequest

        private var curl: Curl = sys.curl

        # Shall this request be verbose?
        var verbose: Bool = false is writable

        # Intern perform method, lowest level of request launching
        private fun perform: nullable CurlResponseFailed
        do
                if not self.curl.is_ok then return answer_failure(0, "Curl instance is not correctly initialized")

                var err

                err = self.curl.native.easy_setopt(new CURLOption.verbose, self.verbose)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.easy_perform
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                return null
        end

        # Intern method with return a failed answer with given code and message
        private fun answer_failure(error_code: Int, error_msg: String): CurlResponseFailed
        do
                return new CurlResponseFailed(error_code, error_msg)
        end
end

# HTTP request builder
#
# The request itself is sent by either `execute` or `download_to_file`.
# The attributes of this class must be set before calling either of these two methods.
#
# ## Minimal usage example
#
# ~~~
# var request = new CurlHTTPRequest("http://example.org/")
# var response = request.execute
# if response isa CurlResponseSuccess then
#     print "Response status code: {response.status_code}"
#     print response.body_str
# else if response isa CurlResponseFailed then
#     print_error response.error_msg
# end
# ~~~
class CurlHTTPRequest
        super CurlRequest
        super NativeCurlCallbacks

        # Address of the remote resource to request
        var url: String

        # Data for the body of a POST request
        var data: nullable HeaderMap is writable

        # Header content of the request
        var headers: nullable HeaderMap is writable

        # Delegates to customize the behavior when running `execute`
        var delegate: nullable CurlCallbacks is writable

        # Set the user agent for all following HTTP requests
        var user_agent: nullable String is writable

        # Execute HTTP request
        #
        # By default, the response body is returned in an instance of `CurlResponse`.
        # This behavior can be customized by setting a custom `delegate`.
        fun execute: CurlResponse
        do
                if not self.curl.is_ok then return answer_failure(0, "Curl instance is not correctly initialized")

                var success_response = new CurlResponseSuccess
                var callback_receiver: CurlCallbacks = success_response
                if self.delegate != null then callback_receiver = self.delegate.as(not null)

                var err

                err = self.curl.native.easy_setopt(new CURLOption.follow_location, 1)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.easy_setopt(new CURLOption.url, url)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                var user_agent = user_agent
                if user_agent != null then
                        err = curl.native.easy_setopt(new CURLOption.user_agent, user_agent)
                        if not err.is_ok then return answer_failure(err.to_i, err.to_s)
                end

                # Callbacks
                err = self.curl.native.register_callback_header(callback_receiver)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.register_callback_body(callback_receiver)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                # HTTP Header
                var headers = self.headers
                if headers != null then
                        var headers_joined = headers.join_pairs(": ")
                        err = self.curl.native.easy_setopt(new CURLOption.httpheader, headers_joined.to_curlslist)
                        if not err.is_ok then return answer_failure(err.to_i, err.to_s)
                end

                # Datas
                var data = self.data
                if data != null then
                        var postdatas = data.to_url_encoded(self.curl)
                        err = self.curl.native.easy_setopt(new CURLOption.postfields, postdatas)
                        if not err.is_ok then return answer_failure(err.to_i, err.to_s)
                end

                var err_resp = perform
                if err_resp != null then return err_resp

                var st_code = self.curl.native.easy_getinfo_long(new CURLInfoLong.response_code)
                if not st_code == null then success_response.status_code = st_code

                return success_response
        end

        # Download to file given resource
        fun download_to_file(output_file_name: nullable String): CurlResponse
        do
                var success_response = new CurlFileResponseSuccess

                var callback_receiver: CurlCallbacks = success_response
                if self.delegate != null then callback_receiver = self.delegate.as(not null)

                var err

                err = self.curl.native.easy_setopt(new CURLOption.follow_location, 1)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.easy_setopt(new CURLOption.url, url)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.register_callback_header(callback_receiver)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.register_callback_stream(callback_receiver)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                var opt_name
                if not output_file_name == null then
                        opt_name = output_file_name
                else if not self.url.substring(self.url.length-1, self.url.length) == "/" then
                        opt_name = self.url.basename
                else
                        return answer_failure(0, "Unable to extract file name, please specify one")
                end

                success_response.file = new FileWriter.open(opt_name)
                if not success_response.file.is_writable then
                        return answer_failure(0, "Unable to create associated file")
                end

                var err_resp = perform
                if err_resp != null then return err_resp

                var st_code = self.curl.native.easy_getinfo_long(new CURLInfoLong.response_code)
                if not st_code == null then success_response.status_code = st_code

                var speed = self.curl.native.easy_getinfo_double(new CURLInfoDouble.speed_download)
                if not speed == null then success_response.speed_download = speed

                var size = self.curl.native.easy_getinfo_double(new CURLInfoDouble.size_download)
                if not size == null then success_response.size_download = size

                var time = self.curl.native.easy_getinfo_double(new CURLInfoDouble.total_time)
                if not time == null then success_response.total_time = time

                success_response.file.close

                return success_response
        end
end

# CURL Mail Request
#
# ~~~
# # Craft mail
# var mail = new CurlMail("sender@example.org",
#                            to=["to@example.org"], cc=["bob@example.org"])
#
# mail.headers_body["Content-Type:"] = """text/html; charset="UTF-8""""
# mail.headers_body["Content-Transfer-Encoding:"] = "quoted-printable"
#
# mail.body = "<h1>Here you can write HTML stuff.</h1>"
# mail.subject = "Hello From My Nit Program"
#
# # Set mail server
# var error = mail.set_outgoing_server("smtps://smtp.example.org:465",
#                                      "user@example.org", "mypassword")
# if error != null then
#     print "Mail Server Error: {error}"
#     exit 0
# end
#
# # Send
# error = mail.execute
# if error != null then
#     print "Transfer Error: {error}"
#     exit 0
# end
# ~~~
class CurlMail
        super CurlRequest
        super NativeCurlCallbacks

        # Address of the sender
        var from: nullable String is writable

        # Main recipients
        var to: nullable Array[String] is writable

        # Subject line
        var subject: nullable String is writable

        # Text content
        var body: nullable String is writable

        # CC recipients
        var cc: nullable Array[String] is writable

        # BCC recipients (hidden from other recipients)
        var bcc: nullable Array[String] is writable

        # HTTP header
        var headers = new HeaderMap is lazy, writable

        # Content header
        var headers_body = new HeaderMap is lazy, writable

        # Protocols supported to send mail to a server
        #
        # Default value at `["smtp", "smtps"]`
        var supported_outgoing_protocol: Array[String] = ["smtp", "smtps"]

        # Helper method to add pair values to mail content while building it (ex: "To:", "address@mail.com")
        private fun add_pair_to_content(str: String, att: String, val: nullable String): String
        do
                if val != null then return "{str}{att}{val}\n"
                return "{str}{att}\n"
        end

        # Helper method to add entire list of pairs to mail content
        private fun add_pairs_to_content(content: String, pairs: HeaderMap): String
        do
                for h_key, h_val in pairs do content = add_pair_to_content(content, h_key, h_val)
                return content
        end

        # Check for host and protocol availability
        private fun is_supported_outgoing_protocol(host: String): CURLCode
        do
                var host_reach = host.split_with("://")
                if host_reach.length > 1 and supported_outgoing_protocol.has(host_reach[0]) then return once new CURLCode.ok
                return once new CURLCode.unsupported_protocol
        end

        # Configure server host and user credentials if needed.
        fun set_outgoing_server(host: String, user: nullable String, pwd: nullable String): nullable CurlResponseFailed
        do
                # Check Curl initialisation
                if not self.curl.is_ok then return answer_failure(0, "Curl instance is not correctly initialized")

                var err

                # Host & Protocol
                err = is_supported_outgoing_protocol(host)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.easy_setopt(new CURLOption.url, host)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                # Credentials
                if not user == null and not pwd == null then
                        err = self.curl.native.easy_setopt(new CURLOption.username, user)
                        if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                        err = self.curl.native.easy_setopt(new CURLOption.password, pwd)
                        if not err.is_ok then return answer_failure(err.to_i, err.to_s)
                end

                return null
        end

        # Execute Mail request with settings configured through attribute
        fun execute: nullable CurlResponseFailed
        do
                if not self.curl.is_ok then return answer_failure(0, "Curl instance is not correctly initialized")

                var lines = new Array[String]

                # Headers
                var headers = self.headers
                if not headers.is_empty then
                        for k, v in headers do lines.add "{k}{v}"
                end

                # Recipients
                var all_recipients = new Array[String]
                var to = self.to
                if to != null and to.length > 0 then
                        lines.add "To:{to.join(",")}"
                        all_recipients.append to
                end

                var cc = self.cc
                if cc != null and cc.length > 0 then
                        lines.add "Cc:{cc.join(",")}"
                        all_recipients.append cc
                end

                var bcc = self.bcc
                if bcc != null and bcc.length > 0 then all_recipients.append bcc

                if all_recipients.is_empty then return answer_failure(0, "There must be at lease one recipient")

                var err = self.curl.native.easy_setopt(new CURLOption.follow_location, 1)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                err = self.curl.native.easy_setopt(new CURLOption.mail_rcpt, all_recipients.to_curlslist)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                # From
                var from = self.from
                if not from == null then
                        lines.add "From:{from}"

                        err = self.curl.native.easy_setopt(new CURLOption.mail_from, from)
                        if not err.is_ok then return answer_failure(err.to_i, err.to_s)
                end

                # Subject
                var subject = self.subject
                if subject == null then subject = "" # Default
                lines.add "Subject: {subject}"

                # Headers body
                var headers_body = self.headers_body
                if not headers_body.is_empty then
                        for k, v in headers_body do lines.add "{k}{v}"
                end

                # Body
                var body = self.body
                if body == null then body = "" # Default

                lines.add ""
                lines.add body
                lines.add ""

                err = self.curl.native.register_callback_read(self)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                var content = lines.join("\n")
                err = self.curl.native.register_read_datas_callback(self, content)
                if not err.is_ok then return answer_failure(err.to_i, err.to_s)

                var err_resp = perform
                if err_resp != null then return err_resp

                return null
        end
end

# Callbacks Interface, allow you to manage in your way the different streams
interface CurlCallbacks
        super NativeCurlCallbacks
end

# Abstract Curl request response
abstract class CurlResponse
end

# Failed Response Class returned when errors during configuration are raised
class CurlResponseFailed
        super CurlResponse

        var error_code: Int
        var error_msg: String

        redef fun to_s do return "{error_msg} ({error_code})"
end

# Success Abstract Response Success Class
abstract class CurlResponseSuccessIntern
        super CurlCallbacks
        super CurlResponse

        var headers = new HashMap[String, String]

        # Receive headers from request due to headers callback registering
        redef fun header_callback(line)
        do
                var splitted = line.split_with(':')
                if splitted.length > 1 then
                        var key = splitted.shift
                        self.headers[key] = splitted.to_s
                end
        end
end

# Success Response Class of a basic response
class CurlResponseSuccess
        super CurlResponseSuccessIntern

        var body_str = ""
        var status_code = 0

        # Receive body from request due to body callback registering
        redef fun body_callback(line) do
                self.body_str = "{self.body_str}{line}"
        end
end

# Success Response Class of a downloaded File
class CurlFileResponseSuccess
        super CurlResponseSuccessIntern

        var status_code = 0
        var speed_download = 0.0
        var size_download = 0.0
        var total_time = 0.0
        private var file: nullable FileWriter = null

        # Receive bytes stream from request due to stream callback registering
        redef fun stream_callback(buffer)
        do
                file.write buffer
        end
end

# Pseudo map associating `String` to `String` for HTTP exchanges
#
# This structure differs from `Map` as each key can have multiple associations
# and the order of insertion is important to some services.
class HeaderMap
        private var array = new Array[Couple[String, String]]

        # Add a `value` associated to `key`
        fun []=(key, value: String)
        do
                array.add new Couple[String, String](key, value)
        end

        # Get a list of the keys associated to `key`
        fun [](k: String): Array[String]
        do
                var res = new Array[String]
                for c in array do if c.first == k then res.add c.second
                return res
        end

        # Iterate over all the associations in `self`
        fun iterator: MapIterator[String, String] do return new HeaderMapIterator(self)

        # Get `self` as a single string for HTTP POST
        #
        # Require: `curl.is_ok`
        fun to_url_encoded(curl: Curl): String
        do
                assert curl.is_ok

                var lines = new Array[String]
                for k, v in self do
                        if k.length == 0 then continue

                        k = curl.native.escape(k)
                        v = curl.native.escape(v)
                        lines.add "{k}={v}"
                end
                return lines.join("&")
        end

        # Concatenate couple of 'key value' separated by 'sep' in Array
        fun join_pairs(sep: String): Array[String]
        do
                var col = new Array[String]
                for k, v in self do col.add("{k}{sep}{v}")
                return col
        end

        # Number of values in `self`
        fun length: Int do return array.length

        # Is this map empty?
        fun is_empty: Bool do return array.is_empty
end

private class HeaderMapIterator
        super MapIterator[String, String]

        var map: HeaderMap
        var iterator: Iterator[Couple[String, String]] = map.array.iterator is lazy

        redef fun is_ok do return self.iterator.is_ok
        redef fun next do self.iterator.next
        redef fun item do return self.iterator.item.second
        redef fun key do return self.iterator.item.first
end