mirror of
https://github.com/gohugoio/hugo.git
synced 2024-11-07 20:30:36 -05:00
301 lines
8 KiB
Markdown
301 lines
8 KiB
Markdown
---
|
|
title: transform.Unmarshal
|
|
description: Parses serialized data and returns a map or an array. Supports CSV, JSON, TOML, YAML, and XML.
|
|
categories: []
|
|
keywords: []
|
|
action:
|
|
aliases: [unmarshal]
|
|
related:
|
|
- functions/transform/Remarshal
|
|
- functions/resources/Get
|
|
- functions/resources/GetRemote
|
|
- functions/encoding/Jsonify
|
|
returnType: any
|
|
signatures: ['transform.Unmarshal [OPTIONS] INPUT']
|
|
toc: true
|
|
aliases: [/functions/transform.unmarshal]
|
|
---
|
|
|
|
The input can be a string or a [resource].
|
|
|
|
## Unmarshal a string
|
|
|
|
```go-html-template
|
|
{{ $string := `
|
|
title: Les Misérables
|
|
author: Victor Hugo
|
|
`}}
|
|
|
|
{{ $book := unmarshal $string }}
|
|
{{ $book.title }} → Les Misérables
|
|
{{ $book.author }} → Victor Hugo
|
|
```
|
|
|
|
## Unmarshal a resource
|
|
|
|
Use the `transform.Unmarshal` function with global, page, and remote resources.
|
|
|
|
### Global resource
|
|
|
|
A global resource is a file within the assets directory, or within any directory mounted to the assets directory.
|
|
|
|
```text
|
|
assets/
|
|
└── data/
|
|
└── books.json
|
|
```
|
|
|
|
```go-html-template
|
|
{{ $data := dict }}
|
|
{{ $path := "data/books.json" }}
|
|
{{ with resources.Get $path }}
|
|
{{ with . | transform.Unmarshal }}
|
|
{{ $data = . }}
|
|
{{ end }}
|
|
{{ else }}
|
|
{{ errorf "Unable to get global resource %q" $path }}
|
|
{{ end }}
|
|
|
|
{{ range where $data "author" "Victor Hugo" }}
|
|
{{ .title }} → Les Misérables
|
|
{{ end }}
|
|
```
|
|
|
|
### Page resource
|
|
|
|
A page resource is a file within a [page bundle].
|
|
|
|
```text
|
|
content/
|
|
├── post/
|
|
│ └── book-reviews/
|
|
│ ├── books.json
|
|
│ └── index.md
|
|
└── _index.md
|
|
```
|
|
|
|
```go-html-template
|
|
{{ $data := dict }}
|
|
{{ $path := "books.json" }}
|
|
{{ with .Resources.Get $path }}
|
|
{{ with . | transform.Unmarshal }}
|
|
{{ $data = . }}
|
|
{{ end }}
|
|
{{ else }}
|
|
{{ errorf "Unable to get page resource %q" $path }}
|
|
{{ end }}
|
|
|
|
{{ range where $data "author" "Victor Hugo" }}
|
|
{{ .title }} → Les Misérables
|
|
{{ end }}
|
|
```
|
|
|
|
### Remote resource
|
|
|
|
A remote resource is a file on a remote server, accessible via HTTP or HTTPS.
|
|
|
|
```go-html-template
|
|
{{ $data := dict }}
|
|
{{ $url := "https://example.org/books.json" }}
|
|
{{ with resources.GetRemote $url }}
|
|
{{ with .Err }}
|
|
{{ errorf "%s" . }}
|
|
{{ else }}
|
|
{{ $data = . | transform.Unmarshal }}
|
|
{{ end }}
|
|
{{ else }}
|
|
{{ errorf "Unable to get remote resource %q" $url }}
|
|
{{ end }}
|
|
|
|
{{ range where $data "author" "Victor Hugo" }}
|
|
{{ .title }} → Les Misérables
|
|
{{ end }}
|
|
```
|
|
|
|
{{% note %}}
|
|
When retrieving remote data, a misconfigured server may send a response header with an incorrect [Content-Type]. For example, the server may set the Content-Type header to `application/octet-stream` instead of `application/json`.
|
|
|
|
In these cases, pass the resource `Content` through the `transform.Unmarshal` function instead of passing the resource itself. For example, in the above, do this instead:
|
|
|
|
`{{ $data = .Content | transform.Unmarshal }}`
|
|
|
|
[Content-Type]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Type
|
|
{{% /note %}}
|
|
|
|
## Options
|
|
|
|
When unmarshaling a CSV file, provide an optional map of options.
|
|
|
|
delimiter
|
|
: (`string`) The delimiter used, default is `,`.
|
|
|
|
comment
|
|
: (`string`) The comment character used in the CSV. If set, lines beginning with the comment character without preceding whitespace are ignored.
|
|
|
|
lazyQuotes {{< new-in 0.122.0 >}}
|
|
: (`bool`) If true, a quote may appear in an unquoted field and a non-doubled quote may appear in a quoted field. Default is `false`.
|
|
|
|
```go-html-template
|
|
{{ $csv := "a;b;c" | transform.Unmarshal (dict "delimiter" ";") }}
|
|
```
|
|
|
|
## Working with XML
|
|
|
|
When unmarshaling an XML file, do not include the root node when accessing data. For example, after unmarshaling the RSS feed below, access the feed title with `$data.channel.title`.
|
|
|
|
```xml
|
|
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
|
|
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
|
|
<channel>
|
|
<title>Books on Example Site</title>
|
|
<link>https://example.org/books/</link>
|
|
<description>Recent content in Books on Example Site</description>
|
|
<language>en-US</language>
|
|
<atom:link href="https://example.org/books/index.xml" rel="self" type="application/rss+xml" />
|
|
<item>
|
|
<title>The Hunchback of Notre Dame</title>
|
|
<description>Written by Victor Hugo</description>
|
|
<link>https://example.org/books/the-hunchback-of-notre-dame/</link>
|
|
<pubDate>Mon, 09 Oct 2023 09:27:12 -0700</pubDate>
|
|
<guid>https://example.org/books/the-hunchback-of-notre-dame/</guid>
|
|
</item>
|
|
<item>
|
|
<title>Les Misérables</title>
|
|
<description>Written by Victor Hugo</description>
|
|
<link>https://example.org/books/les-miserables/</link>
|
|
<pubDate>Mon, 09 Oct 2023 09:27:11 -0700</pubDate>
|
|
<guid>https://example.org/books/les-miserables/</guid>
|
|
</item>
|
|
</channel>
|
|
</rss>
|
|
```
|
|
|
|
Get the remote data:
|
|
|
|
```go-html-template
|
|
{{ $data := dict }}
|
|
{{ $url := "https://example.org/books/index.xml" }}
|
|
{{ with resources.GetRemote $url }}
|
|
{{ with .Err }}
|
|
{{ errorf "%s" . }}
|
|
{{ else }}
|
|
{{ $data = . | transform.Unmarshal }}
|
|
{{ end }}
|
|
{{ else }}
|
|
{{ errorf "Unable to get remote resource %q" $url }}
|
|
{{ end }}
|
|
```
|
|
|
|
Inspect the data structure:
|
|
|
|
```go-html-template
|
|
<pre>{{ debug.Dump $data }}</pre>
|
|
```
|
|
|
|
List the book titles:
|
|
|
|
```go-html-template
|
|
{{ with $data.channel.item }}
|
|
<ul>
|
|
{{ range . }}
|
|
<li>{{ .title }}</li>
|
|
{{ end }}
|
|
</ul>
|
|
{{ end }}
|
|
```
|
|
|
|
Hugo renders this to:
|
|
|
|
```html
|
|
<ul>
|
|
<li>The Hunchback of Notre Dame</li>
|
|
<li>Les Misérables</li>
|
|
</ul>
|
|
```
|
|
|
|
### XML attributes and namespaces
|
|
|
|
Let's add a `lang` attribute to the `title` nodes of our RSS feed, and a namespaced node for the ISBN number:
|
|
|
|
```xml
|
|
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
|
|
<rss version="2.0"
|
|
xmlns:atom="http://www.w3.org/2005/Atom"
|
|
xmlns:isbn="http://schemas.isbn.org/ns/1999/basic.dtd"
|
|
>
|
|
<channel>
|
|
<title>Books on Example Site</title>
|
|
<link>https://example.org/books/</link>
|
|
<description>Recent content in Books on Example Site</description>
|
|
<language>en-US</language>
|
|
<atom:link href="https://example.org/books/index.xml" rel="self" type="application/rss+xml" />
|
|
<item>
|
|
<title lang="fr">The Hunchback of Notre Dame</title>
|
|
<description>Written by Victor Hugo</description>
|
|
<isbn:number>9780140443530</isbn:number>
|
|
<link>https://example.org/books/the-hunchback-of-notre-dame/</link>
|
|
<pubDate>Mon, 09 Oct 2023 09:27:12 -0700</pubDate>
|
|
<guid>https://example.org/books/the-hunchback-of-notre-dame/</guid>
|
|
</item>
|
|
<item>
|
|
<title lang="en">Les Misérables</title>
|
|
<description>Written by Victor Hugo</description>
|
|
<isbn:number>9780451419439</isbn:number>
|
|
<link>https://example.org/books/les-miserables/</link>
|
|
<pubDate>Mon, 09 Oct 2023 09:27:11 -0700</pubDate>
|
|
<guid>https://example.org/books/les-miserables/</guid>
|
|
</item>
|
|
</channel>
|
|
</rss>
|
|
```
|
|
|
|
After retrieving the remote data, inspect the data structure:
|
|
|
|
```go-html-template
|
|
<pre>{{ debug.Dump $data }}</pre>
|
|
```
|
|
|
|
Each item node looks like this:
|
|
|
|
```json
|
|
{
|
|
"description": "Written by Victor Hugo",
|
|
"guid": "https://example.org/books/the-hunchback-of-notre-dame/",
|
|
"link": "https://example.org/books/the-hunchback-of-notre-dame/",
|
|
"number": "9780140443530",
|
|
"pubDate": "Mon, 09 Oct 2023 09:27:12 -0700",
|
|
"title": {
|
|
"#text": "The Hunchback of Notre Dame",
|
|
"-lang": "fr"
|
|
}
|
|
}
|
|
```
|
|
|
|
The title keys do not begin with an underscore or a letter---they are not valid [identifiers]. Use the [`index`] function to access the values:
|
|
|
|
```go-html-template
|
|
{{ with $data.channel.item }}
|
|
<ul>
|
|
{{ range . }}
|
|
{{ $title := index .title "#text" }}
|
|
{{ $lang := index .title "-lang" }}
|
|
{{ $ISBN := .number }}
|
|
<li>{{ $title }} ({{ $lang }}) {{ $ISBN }}</li>
|
|
{{ end }}
|
|
</ul>
|
|
{{ end }}
|
|
```
|
|
|
|
Hugo renders this to:
|
|
|
|
```html
|
|
<ul>
|
|
<li>The Hunchback of Notre Dame (fr) 9780140443530</li>
|
|
<li>Les Misérables (en) 9780451419439</li>
|
|
</ul>
|
|
```
|
|
|
|
[`index`]: /functions/collections/indexfunction/
|
|
[identifiers]: https://go.dev/ref/spec#Identifiers
|
|
[resource]: /getting-started/glossary/#resource
|
|
[page bundle]: /content-management/page-bundles/
|