无法在客户端上访问gatsby环境变量 [英] Can't access gatsby environment variables on the client side

问题描述

我按如下所示设置.env文件和gatsby-config.js.

I set up .env file and gatsby-config.js as below.

// .env.development
GATSBY_API_URL=https://example.com/api

// gatsby-config.js
console.log(process.env)
...
...

尽管运行gatsby develop时，它会显示所有环境变量，包括GATSBY_API_URL: 'https://example.com/api'， 但浏览器上没有env vars.

Although when to run gatsby develop, it shows all env vars including GATSBY_API_URL: 'https://example.com/api', but there is no env vars on a browser.

// client side
console.log(process.env)  // => this will return {}  empty object

我认为我遵循了 https://www.gatsbyjs.org/docs/environment-variables /，并在变量中添加了GATSBY_前缀.

I think I followed https://www.gatsbyjs.org/docs/environment-variables/ as it says, and added GATSBY_ prefix to the var.

我为什么没有在客户端看到env var?

Is there a reason why I don't see the env var on the client side?

gatsby info --clipboard

  System:
    OS: macOS Sierra 10.12.6
    CPU: (4) x64 Intel(R) Core(TM) i5-4258U CPU @ 2.40GHz
    Shell: 5.2 - /bin/zsh
  Binaries:
    Node: 11.2.0 - /usr/local/bin/node
    Yarn: 1.9.4 - /usr/local/bin/yarn
    npm: 6.4.1 - /usr/local/bin/npm
  Browsers:
    Chrome: 70.0.3538.110
    Firefox: 63.0.3
    Safari: 12.0.2
  npmPackages:
    gatsby: ^2.0.61 => 2.0.61
    gatsby-image: ^2.0.22 => 2.0.22
    gatsby-plugin-google-analytics: ^2.0.8 => 2.0.8
    gatsby-plugin-manifest: ^2.0.11 => 2.0.11
    gatsby-plugin-no-sourcemaps: ^2.0.1 => 2.0.1
    gatsby-plugin-nprogress: ^2.0.7 => 2.0.7
    gatsby-plugin-react-helmet: ^3.0.4 => 3.0.4
    gatsby-plugin-sass: ^2.0.5 => 2.0.5
    gatsby-plugin-sharp: ^2.0.14 => 2.0.14
    gatsby-plugin-styled-components: ^3.0.4 => 3.0.4
    gatsby-plugin-typescript: ^2.0.2 => 2.0.2
    gatsby-plugin-typography: ^2.2.2 => 2.2.2
    gatsby-plugin-webpack-bundle-analyzer: ^1.0.3 => 1.0.3
    gatsby-source-filesystem: ^2.0.10 => 2.0.10
    gatsby-transformer-sharp: ^2.1.9 => 2.1.9
    gatsby-transformer-yaml: ^2.1.6 => 2.1.6
  npmGlobalPackages:
    gatsby-cli: 2.4.5

推荐答案

一些步骤&可以解决您问题的注释:

A few steps & notes that should solve your problem:

要查看其是否确实有效，您应该直接打印变量，例如console.log(process.env.API_URL).

To see if it's really working, you should print the variables directly, e.g. console.log(process.env.API_URL).

换句话说，您的文件夹层次结构应类似于:

In other words, your folder hierarchy should look something like:

.env.development
.env.production
src/
  pages/
    index.js

如果要在服务器端访问环境变量，则无需前缀GATSBY _

从文档中

You don't need to prefix with GATSBY_ if you want to access env variables server-side

From the docs:

除了.env.*文件中定义的这些项目环境变量外，您还可以定义OS Env Vars.带有GATSBY_前缀的OS Env Vars将在浏览器JavaScript中可用.

In addition to these Project Environment Variables defined in .env.* files, you could also define OS Env Vars. OS Env Vars which are prefixed with GATSBY_ will become available in browser JavaScript.

如果在浏览器端使用它们，则需要GATSBY_ *前缀

仅当您使用OS Env Vars方法时才使用前缀(即，直接在服务器上而不是在这些.env文件中设置它们).

You need the GATSBY_* prefix if you are using them browser-side

The prefixing is only if you use the OS Env Vars approach (i.e. you set them directly on your server and not in these .env files).

在CodeSandbox上进行复制时，我遇到了这个问题(在CodeSandbox中，您可以通过转到左侧的服务器控制面板"，然后单击重新启动沙箱"来进行重新启动).

I ran into this when reproducing on CodeSandbox (in CodeSandbox, you do the restart by going to Server Control Panel on the left, and clicking Restart Sandbox).

这是工作示例: https://codesandbox.io/s/jj8xzn2y15

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