homework-jianmu/docs/en/08-develop/01-connect/index.md

title	sidebar_label	description
Connect to TDengine	Connect	This document describes how to establish connections to TDengine and how to install and use TDengine client libraries.

import Tabs from "@theme/Tabs"; import TabItem from "@theme/TabItem"; import ConnJava from "./_connect_java.mdx"; import ConnGo from "./_connect_go.mdx"; import ConnRust from "./_connect_rust.mdx"; import ConnNode from "./_connect_node.mdx"; import ConnPythonNative from "./_connect_python.mdx"; import ConnCSNative from "./_connect_cs.mdx"; import ConnC from "./_connect_c.mdx"; import ConnR from "./_connect_r.mdx"; import ConnPHP from "./_connect_php.mdx"; import InstallOnLinux from "../../14-reference/05-connectors/_linux_install.mdx"; import InstallOnWindows from "../../14-reference/05-connectors/_windows_install.mdx"; import InstallOnMacOS from "../../14-reference/05-connectors/_macos_install.mdx"; import VerifyLinux from "../../14-reference/05-connectors/_verify_linux.mdx"; import VerifyWindows from "../../14-reference/05-connectors/_verify_windows.mdx"; import VerifyMacOS from "../../14-reference/05-connectors/_verify_macos.mdx";

Any application running on any platform can access TDengine through the REST API provided by TDengine. For information, see REST API. Applications can also use the client libraries for various programming languages, including C/C++, Java, Python, Go, Node.js, C#, and Rust, to access TDengine. These client libraries support connecting to TDengine clusters using both native interfaces (taosc). Some client libraries also support connecting over a REST interface. Community developers have also contributed several unofficial client libraries, such as the ADO.NET, Lua, and PHP libraries.

Establish Connection

There are three ways for a client library to establish connections to TDengine:

1. Native connection through the TDengine client driver (taosc).
2. REST connection through the REST API provided by the taosAdapter component.
3. Websocket connection provided by the taosAdapter component.

For these ways of connections, client libraries provide similar APIs for performing operations and running SQL statements on your databases. The main difference is the method of establishing the connection, which is not visible to users.

Key differences:

1. For a Native connection, the client driver taosc and the server TDengine version must be compatible.
2. For a REST connection, users do not need to install the client driver taosc, providing the advantage of cross-platform ease of use. However, functions such as data subscription and binary data types are not available. Additionally, compared to Native and Websocket connections, a REST connection has the worst performance.
3. For a Websocket connection, users also do not need to install the client driver taosc.
4. To connect to a cloud service instance, you need to use the REST connection or Websocket connection.

Normally we recommend using Websocket connection.

Install Client Driver taosc

If you are choosing to use the native connection and the the application is not on the same host as TDengine server, the TDengine client driver taosc needs to be installed on the application host. If choosing to use the REST connection or the application is on the same host as TDengine server, this step can be skipped. It's better to use same version of taosc as the TDengine server.

Install

Verify

After the above installation and configuration are done and making sure TDengine service is already started and in service, the TDengine command-line interface taos can be launched to access TDengine.

Install Client Library

If maven is used to manage the projects, what needs to be done is only adding below dependency in pom.xml.

<dependency>
  <groupId>com.taosdata.jdbc</groupId>
  <artifactId>taos-jdbcdriver</artifactId>
  <version>3.3.3</version>
</dependency>

Install from PyPI using pip:

pip install taospy

Install from Git URL:

pip install git+https://github.com/taosdata/taos-connector-python.git

Just need to add driver-go dependency in go.mod .

module goexample

go 1.17

require github.com/taosdata/driver-go/v3 latest

:::note driver-go uses cgo to wrap the APIs provided by taosc, while cgo needs gcc to compile source code in C language, so please make sure you have proper gcc on your system.

:::

Just need to add taos dependency in Cargo.toml.

[dependencies]
taos = { version = "*"}

:::info Rust client library uses different features to distinguish the way to establish connection. To establish Websocket connection, please enable ws feature.

taos = { version = "*", default-features = false, features = ["ws"] }

:::

Node.js client library provides different ways of establishing connections by providing different packages.

1. Install Node.js Native Client Library

npm install @tdengine/client

:::note It's recommend to use Node whose version is between node-v12.8.0 and node-v13.0.0. :::

2. Install Node.js REST Client Library

npm install @tdengine/rest

Just need to add the reference to TDengine.Connector in the project configuration file.

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <StartupObject>TDengineExample.AsyncQueryExample</StartupObject>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="TDengine.Connector" Version="3.1.0" />
  </ItemGroup>

</Project>

Or add by dotnet command.

dotnet add package TDengine.Connector

:::note The sample code below are based on dotnet6.0, they may need to be adjusted if your dotnet version is not exactly same.

:::

1. Download taos-jdbcdriver-version-dist.jar.
2. Install the dependency package RJDBC:

install.packages("RJDBC")

If the client driver (taosc) is already installed, then the C client library is already available.

**Download Source Code Package and Unzip: **

curl -L -o php-tdengine.tar.gz https://github.com/Yurunsoft/php-tdengine/archive/refs/tags/v1.0.2.tar.gz \
&& mkdir php-tdengine \
&& tar -xzf php-tdengine.tar.gz -C php-tdengine --strip-components=1

Version number v1.0.2 is only for example, it can be replaced to any newer version.

**Non-Swoole Environment: **

phpize && ./configure && make -j && make install

**Specify TDengine Location: **

phpize && ./configure --with-tdengine-dir=/usr/local/Cellar/tdengine/3.0.0.0 && make -j && make install

--with-tdengine-dir= is followed by the TDengine installation location. This way is useful in case TDengine location can't be found automatically or macOS.

**Swoole Environment: **

phpize && ./configure --enable-swoole && make -j && make install

Enable The Extension:

Option One: Add extension=tdengine in php.ini

Option Two: Specify the extension on CLI php -d extension=tdengine test.php

Establish a connection

Prior to establishing connection, please make sure TDengine is already running and accessible. The following sample code assumes TDengine is running on the same host as the client program, with FQDN configured to "localhost" and serverPort configured to "6030".

:::tip If the connection fails, in most cases it's caused by improper configuration for FQDN or firewall. Please refer to the section "Unable to establish connection" in FAQ.

:::