73a01565c Remove comment shortcode documentation 0ca7ccd30 Replace usage of comment shortcode with HTML comments fe10d9899 Remove expired new-in labels 11e89dfcb [editorial] Link to proper render-hook page in relref.md 11a581c2f netlify: Hugo 0.142.0 1a4fcf7f7 Miscellaneous edits 2c7a3165f Markdown linting and cleanup 69d7a781b Replace links to glossary terms with custom render hook syntax 441752d2d Refactor glossary lookup portion of link render hook 80109a14f Fix glossary term linking for plural form cd95f0f34 Update link render hook to support glossary links 53eadb430 Remove the glossary template 1d40a7f3b Improve transform.ToMath examples 586970df2 Misc edits 6a06a8de7 Add glossary link shortcode 4171c0eb7 Improve description of masking with non-transparent images 41c8feb64 Fix example of image.Mask filter 704a81656 Add alignx option to images.Text usage example 7c03eb0cc Clarify context in example of using the try statement 56d9c9b71 Refactor glossary of terms 042a6846b Add expiry dates to deprecated methods pages 365ab345f Remove services key from instagram shortcode page b7fe31e07 Reorder options list for images.Text filter 8051ff818 Format directory names, file names, and file paths as code d09a14623 Update version refs for Hugo and Dart Sass 3bb006974 Add NODE_VERSION to Netlify config examples 3a0f2531e Fix typo 7e3198eaf Fix typo cf56452a3 Fix typo a9f51d13e Fix typo 82bfdd8c3 Fix typo a5c41a053 Fix typo abcfed7a5 Fix typo 8c1debf3a Remove outdated new-in badges 809ddf9ef Update theme 63867d56f Use warnf instead of errorf in try-catch example dee3e5f09 Update theme 9791f7057 Remove TODO from comment shortcode examples a346ca1fd Elevate embedded shortcode documentation to its own section 8fa19b50f hugoreleaser.toml => hugoreleaser.yaml 575d60345 Update docs for v0.141.0 a0a442d62 netlify: Hugo 0.141.0 6667cbcd8 Merge commit '81a7b6390036138356773c87a886679c81c524e1' f36fc013e docs: Regen CLI docs 365a47ded tpl/images: Change signature of images.QR to images.QR TEXT OPTIONS ae8f8af0a images.Text: Add "alignx" option for horizontal alignment 8f45ccca6 docs: Regen CLI docs f0e6304f4 Merge commit 'e9fbadacc3f09191e2e19f112a49777eeb8df06c' cb9bec2b2 tpl/images: Add images.QR function git-subtree-dir: docs git-subtree-split: 73a01565c5ba0774d65aa6f2384c44804fefa37d
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title | description | categories | keywords | action | toc | |||||||||
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try | Returns a TryValue object after evaluating the given expression. |
|
true |
{{< new-in 0.141.0 >}}
The try
statement is a non-standard extension to Go's text/template package. It introduces a mechanism for handling errors within templates, mimicking the try-catch
constructs found in other programming languages.
Methods
The TryValue
object encapsulates the result of evaluating the expression, and provides two methods:
- Err
- (
string
) Returns a string representation of the error thrown by the expression, if an error occurred, or returnsnil
if the expression evaluated without errors. - Value
- (
any
) Returns the result of the expression if the evaluation was successful, or returnsnil
if an error occurred while evaluating the expression.
Explanation
By way of example, let's divide a number by zero:
{{ $x := 1 }}
{{ $y := 0 }}
{{ $result := div $x $y }}
{{ printf "%v divided by %v equals %v" $x $y .Value }}
As expected, the example above throws an error and fails the build:
Error: error calling div: can't divide the value by 0
Instead of failing the build, we can catch the error and emit a warning:
{{ $x := 1 }}
{{ $y := 0 }}
{{ with try (div $x $y) }}
{{ with .Err }}
{{ warnf "%s" . }}
{{ else }}
{{ printf "%v divided by %v equals %v" $x $y .Value }}
{{ end }}
{{ end }}
The error thrown by the expression is logged to the console as a warning:
WARN error calling div: can't divide the value by 0
Now let's change the arguments to avoid dividing by zero:
{{ $x := 42 }}
{{ $y := 6 }}
{{ with try (div $x $y) }}
{{ with .Err }}
{{ warnf "%s" . }}
{{ else }}
{{ printf "%v divided by %v equals %v" $x $y .Value }}
{{ end }}
{{ end }}
Hugo renders the above to:
42 divided by 6 equals 7
Example
Error handling is essential when using the resources.GetRemote
function to capture remote resources such as data or images. When calling this function, if the HTTP request fails, Hugo will fail the build.
Instead of failing the build, we can catch the error and emit a warning:
{{ $url := "https://broken-example.org/images/a.jpg" }}
{{ with try (resources.GetRemote $url) }}
{{ with .Err }}
{{ warnf "%s" . }}
{{ else with .Value }}
<img src="{{ .RelPermalink }}" width="{{ .Width }}" height="{{ .Height }}" alt="">
{{ else }}
{{ warnf "Unable to get remote resource %q" $url }}
{{ end }}
{{ end }}
In the above, note that the context within the last conditional block is the TryValue
object returned by the try
statement. At this point neither the Err
nor Value
methods returned anything, so the current context is not useful. Use the $
to access the template context if needed.
{{% note %}}
Hugo does not classify an HTTP response with status code 404 as an error. In this case resources.GetRemote
returns nil.
{{% /note %}}