DolphinDB's httpClient plugin enables you to send HTTP requests and emails conveniently.
The DolphinDB httpClient plugin has different branches, such as release200 and release130. Each branch corresponds to a DolphinDB server version. Please make sure you are in the correct branch of the plugin documentation.
Download the precompiled plugin file under DolphinDBPlugin/httpClient/bin/linux64. Load the plugin with the following command in DolphinDB：
loadPlugin("/path/to/PluginHttpClient.txt");
This plugin uses the libcurl library. If the message “curl return: error setting certificate verify locations: CAfile: /etc/ssl/certs/ca-certificates.crt CApath: none“ is displayed when visiting an HTTPS website, it’s because cURL expects the certificate to be at the default path. Please download the root certificate for cURL using this command:
wget https://curl.haxx.se/ca/cacert.pem
Then place the downloaded file under the default directory as mentioned in the error message.
Prerequisites: The static libraries of libcurl, libssl(version 1.0.1 on ARM; version 1.0.2 on x86), libcrypto(version 1.0.1 on ARM; version 1.0.2 on x86) and libz are available.
version 1.0.1 for ARM architecture:
wget https://www.openssl.org/source/old/1.0.1/openssl-1.0.1u.tar.gz
tar -xzf openssl-1.0.2u.tar.gz
cd openssl-1.0.1u
./config shared --prefix=/tmp/ssl -fPIC
make
make install
version 1.0.2 for x86 architecture:
wget https://www.openssl.org/source/old/1.0.2/openssl-1.0.2u.tar.gz
tar -xzf openssl-1.0.2u.tar.gz
cd openssl-1.0.2u
./config shared --prefix=/tmp/ssl -fPIC
make
make install
wget https://github.com/curl/curl/releases/download/curl-7_47_0/curl-7.47.0.tar.gz
tar -zxf curl-7.47.0.tar.gz
cd curl-7.47.0
CFLAGS="-fPIC" ./configure --prefix=/tmp/curl --without-nss --with-ssl=/tmp/ssl --with-ca-bundle=/etc/ssl/certs/ca-certificates.crt //specify the openssl path for https support. also specify the path to the default https certificate
make
make install
wget http://www.zlib.net/zlib-1.2.11.tar.gz
tar -zxf zlib-1.2.11.tar.gz
cd zlib-1.2.11
CFLAGS="-fPIC" ./configure --prefix=/tmp/zlib
make
make install
In the make build script, we need to specify the path of CURL_DIR and SSL_DIR and Z_DIR. For example:
mkdir build
cd build
cmake -DCURL_DIR=/tmp/curl -DSSL_DIR=/tmp/ssl -DZ_DIR=/tmp/zlib ..
make -j
The plugin library libPluginHttpClient.so will be generated under the current directory.
Send HTTP GET request.
Syntax
httpClient::httpGet(url, [params], [timeout], [headers])
Arguments
- url: a string indicating the URL of HTTP request.
- params: a string or dict (whose keys and values are strings) to send in the HTTP request. For example, suppose url is specified as “www.dolphindb.com“:
- if params is a string (e.g., “example“), the URL of the HTTP request would be “www.dolphindb.com?example“;
- if params is a dictionary (e.g., with 2 key-value pairs “name“->”ddb” and “id“->”111”), the URL of the HTTP request would be “www.dolphindb.com?id=111&name=ddb“.
- timeout: a non-negative integer indicating the the maximum time in milliseconds that an HTTP request can take. Default timeout is 0 which means it never times out during transfer.
- headers: a string or dict (whose keys and values are strings) indicating the headers of the HTTP request.
- If it’s a dictionary (e.g., with 2 key-value pairs “groupName“->”dolphindb” and “groupId“->”11”), two headers “groupId:11“ and “groupName:dolphindb“ will be added to the HTTP request ;
- If it’s a string, it must have the pattern
<key>:<value>and it will be added as a header to the request.
Return
A dictionary object containing following keys:
- responseCode: HTTP status code
- headers: HTTP response header
- text: HTTP response body
- elapsed: HTTP request elapsed time
Example
loadPlugin('/home/zmx/worker/DolphinDBPlugin/httpClient/PluginHttpClient.txt');
param=dict(string,string);
header=dict(string,string);
param['name']='zmx';
param['id']='111';
header['groupName']='dolphindb';
header['groupId']='11';
//Please set up your own httpServer ex.(python -m SimpleHTTPServer 8900)
url = "localhost:8900";
res = httpClient::httpGet(url,param,1000,header);
Send HTTP POST request.
Syntax
httpClient::httpPost(url, [params], [timeout], [headers])
Arguments
- url: a string indicating the URL of HTTP request.
- params: a string or dict (whose keys and values are strings) to send in the HTTP request. For example, suppose url is specified as “DolphinDB - High Performance Time-series Database “:
- if params is a string (e.g., “example“), the URL of the HTTP request would be “www.dolphindb.com?example“;
- if params is a dictionary (e.g., with 2 key-value pairs “name“->”ddb” and “id“->”111”), the URL of the HTTP request would be “www.dolphindb.com?id=111&name=ddb“.
- timeout: a non-negative integer indicating the the maximum time in milliseconds that you allow the HTTP request to take. Default timeout is 0 which means it never times out during transfer.
- headers: a string or dict (whose keys and values are strings) indicating the headers of the HTTP request.
- If it’s a dictionary (e.g., with 2 key-value pairs “groupName“->”dolphindb” and “groupId“->”11”), two headers “groupId:11“ and “groupName:dolphindb“ will be added to the HTTP request ;
- If it’s a string, it must have the pattern
<key>:<value>and it will be added as a header to the request.
Return
A dictionary object containing following keys:
- responseCode: HTTP status code
- headers: HTTP response header
- text: HTTP response body
- elapsed: HTTP request elapsed time
Example
loadPlugin('/home/zmx/worker/DolphinDBPlugin/httpClient/PluginHttpClient.txt');
param=dict(string,string);
header=dict(string,string);
param['name']='zmx';
param['id']='111';
header['groupName']='dolphindb';
header['groupId']='11';
//Please set up your own httpServer e.g. (python -m SimpleHTTPServer 8900)
url = "localhost:8900";
res = httpClient::httpPost(url,param,1000,header);
Configure the email server.
Note: To send email using the httpClient plugin, the SMTP service on your mail account must be enabled.
Syntax
httpClient::emailSmtpConfig(emailName,host,post)
Arguments
- emailName: a string indicating the domain name in your email address. For example,
"gmail.com"or"yahoo.com". - host: a string indicating your SMTP server address.
- port: an integer (INT) indicating the port number of your email server. If this parameter is unspecified, it takes the default value of 25.
Examples
emailName="example.com";
host="smtp.example.com";
port=25;
httpClient::emailSmtpConfig(emailName,host,port);
Send an email.
- This plugin uses the SMTP protocol for sending email, so the mail server must support SMTP and have the SMTP port open. If the email service provider does not enable SMTP by default, you will need to enable SMTP service for that email account. Also check if the provider offers authorization codes for accounts. If so, use the authorization code for the pwd parameter instead of the account password.
- If the email is sent successfully, a dictionary "res" will be returned with
res['responseCode']==250.
Syntax
httpClient::sendEmail(userId,pwd,recipient,subject,body)
Arguments
- user: a string indicating the email address for sending the email.
- pwd: a string or a vector of strings. If an SMTP password is provided, specify pwd as the SMTP password. Otherwise, it is the password to your mailbox.
- recipient: a string indicating the mail address(es) to send the mail to.
- subject: a string indicating the subject of the email.
- body: a string indicating the subject of the email.
Return
Return a dictionary “res“ containing the following fields: userId (email address of the sender), recepient, responseCode, headers, text, elapsed (the elapsed time since the request was sent).
If the email is sent successfully, res['responseCode']==250 is returned.
Example
Send mail to one recipient:
res=httpClient::sendEmail('MailFrom@example.com','xxxxx','MailTo@example.com','This is a subject','It is a text');
Send to multiple recipients:
recipients='recepient1@example.com''recepient2@example.com''recepient3@example.com';
res=httpClient::sendEmail('MailFrom@example.com','xxxxx',recipients,'This is a subject','It is a text');