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authorBrian Picciano <mediocregopher@gmail.com>2023-01-21 17:37:22 +0100
committerBrian Picciano <mediocregopher@gmail.com>2023-01-21 17:37:22 +0100
commitffdd9520b9803e141582ba647050682659075760 (patch)
treed19769360077d7b4a4cce58a0e70679014fd5979 /src/post
parent293655452cfc6a106c55384e839f9c07d340b954 (diff)
Implement preprocessing of post bodies for gemini
Diffstat (limited to 'src/post')
-rw-r--r--src/post/preprocess.go66
1 files changed, 66 insertions, 0 deletions
diff --git a/src/post/preprocess.go b/src/post/preprocess.go
new file mode 100644
index 0000000..4d4be9d
--- /dev/null
+++ b/src/post/preprocess.go
@@ -0,0 +1,66 @@
+package post
+
+import (
+ "fmt"
+ "io"
+ "text/template"
+)
+
+// PreprocessFunctions are functions which can be used by posts themselves to
+// interleave dynamic content into their bodies. Usually this is used for
+// properly constructing URLs, but also for things like displaying images.
+type PreprocessFunctions struct {
+
+ // BlogURL returns the given string, rooted to the blog's base url (which
+ // may or may not include path components itself).
+ //
+ // The given path should not have a leading slash.
+ BlogURL func(path string) string
+
+ // AssetURL returns the URL of the asset with the given ID.
+ AssetURL func(id string) string
+
+ // PostURL returns the URL of the post with the given ID.
+ PostURL func(id string) string
+
+ // StaticURL returns the URL of a file being served from the static
+ // directory. The given path should _not_ include the prefixed 'static/'
+ // path element.
+ StaticURL func(path string) string
+
+ // Image returns a string which should be inlined into the post body in
+ // order to display an.
+ //
+ // The first argument to Image _must_ be the ID of an image asset. The
+ // second argument _may_ be a description of the image which will be used as
+ // alt text, or possibly displayed to the user with the image.
+ Image func(args ...string) (string, error)
+}
+
+// PreprocessBody interprets the Post's Body as a text template which may use
+// any of the functions found in PreprocessFunctions (all must be set). It
+// executes the template and writes the result to the given writer.
+func (p Post) PreprocessBody(into io.Writer, funcs PreprocessFunctions) error {
+
+ tpl := template.New("")
+
+ tpl.Funcs(template.FuncMap{
+ "BlogURL": funcs.BlogURL,
+ "AssetURL": funcs.AssetURL,
+ "PostURL": funcs.PostURL,
+ "StaticURL": funcs.StaticURL,
+ "Image": funcs.Image,
+ })
+
+ tpl, err := tpl.Parse(p.Body)
+
+ if err != nil {
+ return fmt.Errorf("parsing post body as template: %w", err)
+ }
+
+ if err := tpl.Execute(into, nil); err != nil {
+ return fmt.Errorf("executing post body as template: %w", err)
+ }
+
+ return nil
+}