feat: Option to inline additional CSS

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Added
 
 - Option to disable processing of "style" tags. [#45](https://github.com/Stranger6667/css-inline/issues/45)
+- Option to inline additional CSS. [#45](https://github.com/Stranger6667/css-inline/issues/45)
 
 ## [0.3.3] - 2020-07-07
 

README.md

@@ -114,6 +114,10 @@ ARGS:
         "inlined.example.html".
 
 OPTIONS:
+    --inline-style-tags
+        Whether to inline CSS from "style" tags. The default value is `true`. To disable inlining
+        from "style" tags use `-inline-style-tags=false`.
+
     --remove-style-tags
         Remove "style" tags after inlining.
 
@@ -122,4 +126,7 @@ OPTIONS:
 
     --load-remote-stylesheets
         Whether remote stylesheets should be loaded or not.
+
+    --extra-css
+        Additional CSS to inline.
 ```

python/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Added
 
 - Option to disable processing of "style" tags. [#45](https://github.com/Stranger6667/css-inline/issues/45)
+- Option to inline additional CSS. [#45](https://github.com/Stranger6667/css-inline/issues/45)
 
 ## [0.3.2] - 2020-07-09
 

python/src/lib.rs

@@ -1,6 +1,7 @@
 use css_inline as rust_inline;
 use pyo3::{create_exception, exceptions, prelude::*, types::PyList, wrap_pyfunction};
 use rayon::prelude::*;
+use std::borrow::Cow;
 
 const MODULE_DOCSTRING: &str = "Fast CSS inlining written in Rust";
 const INLINE_ERROR_DOCSTRING: &str = "An error that can occur during CSS inlining";
@@ -35,13 +36,13 @@ fn parse_url(url: Option<String>) -> PyResult<Option<url::Url>> {
     })
 }
 
-/// CSSInliner(inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True)
+/// CSSInliner(inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True, extra_css=None)
 ///
 /// Customizable CSS inliner.
 #[pyclass]
-#[text_signature = "(inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True)"]
+#[text_signature = "(inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True, extra_css=None)"]
 struct CSSInliner {
-    inner: rust_inline::CSSInliner,
+    inner: rust_inline::CSSInliner<'static>,
 }
 
 #[pymethods]
@@ -52,12 +53,14 @@ impl CSSInliner {
         remove_style_tags: Option<bool>,
         base_url: Option<String>,
         load_remote_stylesheets: Option<bool>,
+        extra_css: Option<String>,
     ) -> PyResult<Self> {
         let options = rust_inline::InlineOptions {
             inline_style_tags: inline_style_tags.unwrap_or(true),
             remove_style_tags: remove_style_tags.unwrap_or(false),
             base_url: parse_url(base_url)?,
             load_remote_stylesheets: load_remote_stylesheets.unwrap_or(true),
+            extra_css: extra_css.map(Cow::Owned),
         };
         Ok(CSSInliner {
             inner: rust_inline::CSSInliner::new(options),
@@ -81,45 +84,49 @@ impl CSSInliner {
     }
 }
 
-/// inline(html, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True)
+/// inline(html, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True, extra_css=None)
 ///
 /// Inline CSS in the given HTML document
 #[pyfunction]
-#[text_signature = "(html, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True)"]
+#[text_signature = "(html, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True, extra_css=None)"]
 fn inline(
     html: &str,
     inline_style_tags: Option<bool>,
     remove_style_tags: Option<bool>,
     base_url: Option<String>,
     load_remote_stylesheets: Option<bool>,
+    extra_css: Option<&str>,
 ) -> PyResult<String> {
     let options = rust_inline::InlineOptions {
         inline_style_tags: inline_style_tags.unwrap_or(true),
         remove_style_tags: remove_style_tags.unwrap_or(false),
         base_url: parse_url(base_url)?,
         load_remote_stylesheets: load_remote_stylesheets.unwrap_or(true),
+        extra_css: extra_css.map(Cow::Borrowed),
     };
     let inliner = rust_inline::CSSInliner::new(options);
     Ok(inliner.inline(html).map_err(InlineErrorWrapper)?)
 }
 
-/// inline_many(htmls, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True)
+/// inline_many(htmls, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True, extra_css=None)
 ///
 /// Inline CSS in multiple HTML documents
 #[pyfunction]
-#[text_signature = "(htmls, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True)"]
+#[text_signature = "(htmls, inline_style_tags=True, remove_style_tags=False, base_url=None, load_remote_stylesheets=True, extra_css=None)"]
 fn inline_many(
     htmls: &PyList,
     inline_style_tags: Option<bool>,
     remove_style_tags: Option<bool>,
     base_url: Option<String>,
     load_remote_stylesheets: Option<bool>,
+    extra_css: Option<&str>,
 ) -> PyResult<Vec<String>> {
     let options = rust_inline::InlineOptions {
         inline_style_tags: inline_style_tags.unwrap_or(true),
         remove_style_tags: remove_style_tags.unwrap_or(false),
         base_url: parse_url(base_url)?,
         load_remote_stylesheets: load_remote_stylesheets.unwrap_or(true),
+        extra_css: extra_css.map(Cow::Borrowed),
     };
     let inliner = rust_inline::CSSInliner::new(options);
     inline_many_impl(&inliner, htmls)

src/lib.rs

@@ -130,7 +130,7 @@ pub use url::{ParseError, Url};
 
 /// Configuration options for CSS inlining process.
 #[derive(Debug)]
-pub struct InlineOptions {
+pub struct InlineOptions<'a> {
     /// Whether to inline CSS from "style" tags
     pub inline_style_tags: bool,
     /// Remove "style" tags after inlining
@@ -139,9 +139,14 @@ pub struct InlineOptions {
     pub base_url: Option<Url>,
     /// Whether remote stylesheets should be loaded or not
     pub load_remote_stylesheets: bool,
+    // The point of using `Cow` here is Python bindings, where it is problematic to pass a reference
+    // without dealing with memory leaks & unsafe. With `Cow` we can use moved values as `String` in
+    // Python wrapper for `CSSInliner` and `&str` in Rust & simple functions on the Python side
+    /// Additional CSS to inline
+    pub extra_css: Option<Cow<'a, str>>,
 }
 
-impl InlineOptions {
+impl InlineOptions<'_> {
     /// Options for "compact" HTML output
     #[inline]
     pub fn compact() -> Self {
@@ -150,18 +155,20 @@ impl InlineOptions {
             remove_style_tags: true,
             base_url: None,
             load_remote_stylesheets: true,
+            extra_css: None,
         }
     }
 }
 
-impl Default for InlineOptions {
+impl Default for InlineOptions<'_> {
     #[inline]
     fn default() -> Self {
         InlineOptions {
             inline_style_tags: true,
             remove_style_tags: false,
             base_url: None,
             load_remote_stylesheets: true,
+            extra_css: None,
         }
     }
 }
@@ -170,14 +177,14 @@ type Result<T> = std::result::Result<T, InlineError>;
 
 /// Customizable CSS inliner.
 #[derive(Debug)]
-pub struct CSSInliner {
-    options: InlineOptions,
+pub struct CSSInliner<'a> {
+    options: InlineOptions<'a>,
 }
 
-impl CSSInliner {
+impl<'a> CSSInliner<'a> {
     /// Create a new `CSSInliner` instance with given options.
     #[inline]
-    pub fn new(options: InlineOptions) -> Self {
+    pub fn new(options: InlineOptions<'a>) -> Self {
         CSSInliner { options }
     }
 
@@ -241,6 +248,9 @@ impl CSSInliner {
                 }
             }
         }
+        if let Some(extra_css) = &self.options.extra_css {
+            process_css(&document, extra_css)?;
+        }
         document.serialize(target)?;
         Ok(())
     }
@@ -315,7 +325,7 @@ fn process_css(document: &NodeRef, css: &str) -> Result<()> {
     Ok(())
 }
 
-impl Default for CSSInliner {
+impl Default for CSSInliner<'_> {
     #[inline]
     fn default() -> Self {
         CSSInliner::new(Default::default())

src/main.rs

@@ -1,5 +1,6 @@
 use css_inline::{CSSInliner, InlineOptions};
 use rayon::prelude::*;
+use std::borrow::Cow;
 use std::error::Error;
 use std::fs::File;
 use std::io::{self, Read};
@@ -38,7 +39,10 @@ OPTIONS:
         Used for loading external stylesheets via relative URLs.
 
     --load-remote-stylesheets
-        Whether remote stylesheets should be loaded or not."#
+        Whether remote stylesheets should be loaded or not.
+
+    --extra-css
+        Additional CSS to inline."#
 );
 
 struct Args {
@@ -47,6 +51,7 @@ struct Args {
     inline_style_tags: bool,
     remove_style_tags: bool,
     base_url: Option<String>,
+    extra_css: Option<String>,
     load_remote_stylesheets: bool,
     files: Vec<String>,
 }
@@ -69,6 +74,7 @@ fn main() -> Result<(), Box<dyn Error>> {
             .unwrap_or(true),
         remove_style_tags: args.contains("--remove-style-tags"),
         base_url: args.opt_value_from_str("--base-url")?,
+        extra_css: args.opt_value_from_str("--extra-css")?,
         load_remote_stylesheets: args.contains("--load-remote-stylesheets"),
         files: args.free()?,
     };
@@ -83,6 +89,7 @@ fn main() -> Result<(), Box<dyn Error>> {
             remove_style_tags: args.remove_style_tags,
             base_url: parse_url(args.base_url)?,
             load_remote_stylesheets: args.load_remote_stylesheets,
+            extra_css: args.extra_css.as_deref().map(Cow::Borrowed),
         };
         let inliner = CSSInliner::new(options);
         if args.files.is_empty() {

tests/test_inlining.rs

@@ -140,6 +140,22 @@ fn do_not_process_style_tag_and_remove() {
     )
 }
 
+#[test]
+fn extra_css() {
+    let html = html!("h1 {background-color: blue;}", "<h1>Hello world!</h1>");
+    let options = InlineOptions {
+        inline_style_tags: false,
+        extra_css: Some("h1 {background-color: green;}".into()),
+        ..Default::default()
+    };
+    let inliner = CSSInliner::new(options);
+    let result = inliner.inline(&html).unwrap();
+    assert_eq!(
+        result,
+        "<html><head><title>Test</title><style>h1 {background-color: blue;}</style></head><body><h1 style=\"background-color: green;\">Hello world!</h1></body></html>"
+    )
+}
+
 #[test]
 fn remote_file_stylesheet() {
     let html = r#"