From 81b610316558d95789b66dc078be8d2549c9ba0b Mon Sep 17 00:00:00 2001
From: Vedha Viyash <49812166+vedhav@users.noreply.github.com>
Date: Tue, 17 Dec 2024 16:48:39 +0530
Subject: [PATCH] feat: allow html content to be added to a report (#294)

---
 R/ContentBlock.R                   |  20 +---
 R/FileBlock.R                      |   3 +
 R/HTMLBlock.R                      |  62 ++++++++++++
 R/Previewer.R                      |   2 +
 R/RcodeBlock.R                     |  16 ++++
 R/Renderer.R                       |  13 ++-
 R/ReportCard.R                     |  11 +++
 R/TextBlock.R                      |  15 +++
 man/ContentBlock.Rd                |  40 +-------
 man/FileBlock.Rd                   |   1 -
 man/HTMLBlock.Rd                   | 147 +++++++++++++++++++++++++++++
 man/RcodeBlock.Rd                  |  42 ++++++++-
 man/ReportCard.Rd                  |  37 ++++++++
 man/TextBlock.Rd                   |  42 ++++++++-
 tests/testthat/test-ContentBlock.R |   8 +-
 tests/testthat/test-HTMLBlock.R    |  40 ++++++++
 tests/testthat/test-RcodeBlock.R   |   2 +-
 tests/testthat/test-Renderer.R     |   5 +-
 tests/testthat/test-ReportCard.R   |   9 +-
 tests/testthat/test-TextBlock.R    |   2 +-
 20 files changed, 446 insertions(+), 71 deletions(-)
 create mode 100644 R/HTMLBlock.R
 create mode 100644 man/HTMLBlock.Rd
 create mode 100644 tests/testthat/test-HTMLBlock.R

diff --git a/R/ContentBlock.R b/R/ContentBlock.R
index 04f9dbbc..9d325599 100644
--- a/R/ContentBlock.R
+++ b/R/ContentBlock.R
@@ -8,22 +8,9 @@
 ContentBlock <- R6::R6Class( # nolint: object_name_linter.
   classname = "ContentBlock",
   public = list(
-    #' @description Initialize a `ContentBlock` object.
-    #'
-    #' @details Returns a `ContentBlock` object with no content and the default style.
-    #'
-    #' @return Object of class `ContentBlock`, invisibly.
-    #' @examples
-    #' ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
-    #' ContentBlock$new()
-    #'
-    initialize = function() {
-      private$content <- character(0)
-      invisible(self)
-    },
     #' @description Sets content of this `ContentBlock`.
     #'
-    #' @param content (`character(0)` or `character(1)`) string or file path assigned to this `ContentBlock`
+    #' @param content (`any`) R object
     #'
     #' @return `self`, invisibly.
     #' @examples
@@ -32,13 +19,12 @@ ContentBlock <- R6::R6Class( # nolint: object_name_linter.
     #' block$set_content("Base64 encoded picture")
     #'
     set_content = function(content) {
-      checkmate::assert_character(content, min.len = 0, max.len = 1)
       private$content <- content
       invisible(self)
     },
     #' @description Retrieves the content assigned to this block.
     #'
-    #' @return `character` string or file path assigned to this `ContentBlock`.
+    #' @return object stored in a `private$content` field
     #' @examples
     #' ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
     #' block <- ContentBlock$new()
@@ -64,7 +50,7 @@ ContentBlock <- R6::R6Class( # nolint: object_name_linter.
     }
   ),
   private = list(
-    content = character(0),
+    content = NULL, # this can be any R object
     # @description The copy constructor.
     #
     # @param name (`character(1)`) the name of the field
diff --git a/R/FileBlock.R b/R/FileBlock.R
index 9a33d195..bd2d1c48 100644
--- a/R/FileBlock.R
+++ b/R/FileBlock.R
@@ -56,6 +56,9 @@ FileBlock <- R6::R6Class( # nolint: object_name_linter.
       list(basename = base_name)
     }
   ),
+  private = list(
+    content = character(0)
+  ),
   lock_objects = TRUE,
   lock_class = TRUE
 )
diff --git a/R/HTMLBlock.R b/R/HTMLBlock.R
new file mode 100644
index 00000000..70a90e33
--- /dev/null
+++ b/R/HTMLBlock.R
@@ -0,0 +1,62 @@
+#' @title `HTMLBlock`
+#' @docType class
+#' @description
+#' Specialized `FileBlock` for managing HTML content in reports.
+#' It's designed to handle various HTML content, and render the report as HTML,
+#' however `htmlwidgets` objects can also be rendered to static document-ready format.
+#'
+#' @keywords internal
+HTMLBlock <- R6::R6Class( # nolint: object_name_linter.
+  classname = "HTMLBlock",
+  inherit = ContentBlock,
+  public = list(
+    #' @description Initialize a `HTMLBlock` object.
+    #'
+    #' @param content An object that can be rendered as a HTML content assigned to
+    #'   this `HTMLBlock`
+    #'
+    #' @return Object of class `HTMLBlock`, invisibly.
+    initialize = function(content) {
+      if (!missing(content)) {
+        checkmate::assert_multi_class(content, private$supported_types)
+        self$set_content(content)
+      }
+      invisible(self)
+    },
+
+    #' @description Create the `HTMLBlock` from a list.
+    #'
+    #' @param x (`named list`) with a single field `content` containing `shiny.tag`,
+    #' `shiny.tag.list` or `htmlwidget`.
+    #'
+    #' @return `self`, invisibly.
+    #' @examples
+    #' HTMLBlock <- getFromNamespace("HTMLBlock", "teal.reporter")
+    #' block <- HTMLBlock$new()
+    #' block$from_list(list(content = shiny::tags$div("test")))
+    #'
+    from_list = function(x) {
+      checkmate::assert_list(x, types = private$supported_types)
+      checkmate::assert_names(names(x), must.include = "content")
+      self$set_content(x$content)
+      invisible(self)
+    },
+
+    #' @description Convert the `HTMLBlock` to a list.
+    #'
+    #' @return `named list` with a text and style.
+    #' @examples
+    #' HTMLBlock <- getFromNamespace("HTMLBlock", "teal.reporter")
+    #' block <- HTMLBlock$new(shiny::tags$div("test"))
+    #' block$to_list()
+    #'
+    to_list = function() {
+      list(content = self$get_content())
+    }
+  ),
+  private = list(
+    supported_types = c("shiny.tag", "shiny.tag.list", "htmlwidget")
+  ),
+  lock_objects = TRUE,
+  lock_class = TRUE
+)
diff --git a/R/Previewer.R b/R/Previewer.R
index 360f0e7d..fc37b626 100644
--- a/R/Previewer.R
+++ b/R/Previewer.R
@@ -319,6 +319,8 @@ block_to_html <- function(b) {
     )
   } else if (inherits(b, "NewpageBlock")) {
     shiny::tags$br()
+  } else if (inherits(b, "HTMLBlock")) {
+    b_content
   } else {
     stop("Unknown block class")
   }
diff --git a/R/RcodeBlock.R b/R/RcodeBlock.R
index 9479e590..19f3b750 100644
--- a/R/RcodeBlock.R
+++ b/R/RcodeBlock.R
@@ -21,10 +21,25 @@ RcodeBlock <- R6::R6Class( # nolint: object_name_linter.
     #' block <- RcodeBlock$new()
     #'
     initialize = function(content = character(0), ...) {
+      checkmate::assert_class(content, "character")
       super$set_content(content)
       self$set_params(list(...))
       invisible(self)
     },
+    #' @description Sets content of this `RcodeBlock`.
+    #'
+    #' @param content (`any`) R object
+    #'
+    #' @return `self`, invisibly.
+    #' @examples
+    #' RcodeBlock <- getFromNamespace("RcodeBlock", "teal.reporter")
+    #' block <- RcodeBlock$new()
+    #' block$set_content("a <- 1")
+    #'
+    set_content = function(content) {
+      checkmate::assert_string(content)
+      super$set_content(content)
+    },
     #' @description Sets the parameters of this `RcodeBlock`.
     #'
     #' @details Configures `rmarkdown` chunk parameters for the `R` code block,
@@ -97,6 +112,7 @@ RcodeBlock <- R6::R6Class( # nolint: object_name_linter.
     }
   ),
   private = list(
+    content = character(0),
     params = list()
   ),
   lock_objects = TRUE,
diff --git a/R/Renderer.R b/R/Renderer.R
index 782a9935..8ff3996b 100644
--- a/R/Renderer.R
+++ b/R/Renderer.R
@@ -81,9 +81,11 @@ Renderer <- R6::R6Class( # nolint: object_name_linter.
     #' result_path <- Renderer$new()$renderRmd(reporter$get_blocks(), yaml_header)
     #'
     renderRmd = function(blocks, yaml_header, global_knitr = getOption("teal.reporter.global_knitr")) {
-      checkmate::assert_list(blocks, c("TextBlock", "PictureBlock", "NewpageBlock", "TableBlock", "RcodeBlock"))
+      checkmate::assert_list(
+        blocks,
+        c("TextBlock", "PictureBlock", "NewpageBlock", "TableBlock", "RcodeBlock", "HTMLBlock")
+      )
       checkmate::assert_subset(names(global_knitr), names(knitr::opts_chunk$get()))
-
       if (missing(yaml_header)) {
         yaml_header <- md_header(yaml::as.yaml(list(title = "Report")))
       }
@@ -220,6 +222,8 @@ Renderer <- R6::R6Class( # nolint: object_name_linter.
         private$tableBlock2md(block)
       } else if (inherits(block, "NewpageBlock")) {
         block$get_content()
+      } else if (inherits(block, "HTMLBlock")) {
+        private$htmlBlock2md(block)
       } else {
         stop("Unknown block class")
       }
@@ -275,6 +279,11 @@ Renderer <- R6::R6Class( # nolint: object_name_linter.
       basename_table <- basename(block$get_content())
       file.copy(block$get_content(), file.path(private$output_dir, basename_table))
       sprintf("```{r echo = FALSE}\nreadRDS('%s')\n```", basename_table)
+    },
+    htmlBlock2md = function(block) {
+      basename <- basename(tempfile(fileext = ".rds"))
+      suppressWarnings(saveRDS(block$get_content(), file = file.path(private$output_dir, basename)))
+      sprintf("```{r echo = FALSE}\nreadRDS('%s')\n```", basename)
     }
   ),
   lock_objects = TRUE,
diff --git a/R/ReportCard.R b/R/ReportCard.R
index 8ff1595e..c0221751 100644
--- a/R/ReportCard.R
+++ b/R/ReportCard.R
@@ -37,6 +37,17 @@ ReportCard <- R6::R6Class( # nolint: object_name_linter.
       self$append_content(TableBlock$new(table))
       invisible(self)
     },
+    #' @description Appends a html content to this `ReportCard`.
+    #'
+    #' @param content An object that can be rendered as a HTML content.
+    #' @return `self`, invisibly.
+    #' @examples
+    #' card <- ReportCard$new()$append_html(shiny::div("HTML Content"))
+    #'
+    append_html = function(content) {
+      self$append_content(HTMLBlock$new(content))
+      invisible(self)
+    },
     #' @description Appends a plot to this `ReportCard`.
     #'
     #' @param plot (`ggplot` or `grob` or `trellis`) plot object.
diff --git a/R/TextBlock.R b/R/TextBlock.R
index 32fd3669..a6d09078 100644
--- a/R/TextBlock.R
+++ b/R/TextBlock.R
@@ -27,6 +27,20 @@ TextBlock <- R6::R6Class( # nolint: object_name_linter.
       self$set_style(style)
       invisible(self)
     },
+    #' @description Sets content of this `TextBlock`.
+    #'
+    #' @param content (`any`) R object
+    #'
+    #' @return `self`, invisibly.
+    #' @examples
+    #' ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
+    #' block <- ContentBlock$new()
+    #' block$set_content("Base64 encoded picture")
+    #'
+    set_content = function(content) {
+      checkmate::assert_string(content)
+      super$set_content(content)
+    },
     #' @description Sets the style of this `TextBlock`.
     #'
     #' @details The style has bearing on the rendering of this block.
@@ -96,6 +110,7 @@ TextBlock <- R6::R6Class( # nolint: object_name_linter.
     }
   ),
   private = list(
+    content = character(0),
     style = character(0),
     styles = c("default", "header2", "header3", "verbatim")
   ),
diff --git a/man/ContentBlock.Rd b/man/ContentBlock.Rd
index fed18515..4a5ee94d 100644
--- a/man/ContentBlock.Rd
+++ b/man/ContentBlock.Rd
@@ -11,14 +11,6 @@ It serves as a foundation for constructing complex report structures.
 }
 \examples{
 
-## ------------------------------------------------
-## Method `ContentBlock$new`
-## ------------------------------------------------
-
-ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
-ContentBlock$new()
-
-
 ## ------------------------------------------------
 ## Method `ContentBlock$set_content`
 ## ------------------------------------------------
@@ -41,40 +33,12 @@ block$get_content()
 \section{Methods}{
 \subsection{Public methods}{
 \itemize{
-\item \href{#method-ContentBlock-new}{\code{ContentBlock$new()}}
 \item \href{#method-ContentBlock-set_content}{\code{ContentBlock$set_content()}}
 \item \href{#method-ContentBlock-get_content}{\code{ContentBlock$get_content()}}
 \item \href{#method-ContentBlock-from_list}{\code{ContentBlock$from_list()}}
 \item \href{#method-ContentBlock-to_list}{\code{ContentBlock$to_list()}}
 \item \href{#method-ContentBlock-clone}{\code{ContentBlock$clone()}}
 }
-}
-\if{html}{\out{<hr>}}
-\if{html}{\out{<a id="method-ContentBlock-new"></a>}}
-\if{latex}{\out{\hypertarget{method-ContentBlock-new}{}}}
-\subsection{Method \code{new()}}{
-Initialize a \code{ContentBlock} object.
-\subsection{Usage}{
-\if{html}{\out{<div class="r">}}\preformatted{ContentBlock$new()}\if{html}{\out{</div>}}
-}
-
-\subsection{Details}{
-Returns a \code{ContentBlock} object with no content and the default style.
-}
-
-\subsection{Returns}{
-Object of class \code{ContentBlock}, invisibly.
-}
-\subsection{Examples}{
-\if{html}{\out{<div class="r example copy">}}
-\preformatted{ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
-ContentBlock$new()
-
-}
-\if{html}{\out{</div>}}
-
-}
-
 }
 \if{html}{\out{<hr>}}
 \if{html}{\out{<a id="method-ContentBlock-set_content"></a>}}
@@ -88,7 +52,7 @@ Sets content of this \code{ContentBlock}.
 \subsection{Arguments}{
 \if{html}{\out{<div class="arguments">}}
 \describe{
-\item{\code{content}}{(\code{character(0)} or \code{character(1)}) string or file path assigned to this \code{ContentBlock}}
+\item{\code{content}}{(\code{any}) R object}
 }
 \if{html}{\out{</div>}}
 }
@@ -117,7 +81,7 @@ Retrieves the content assigned to this block.
 }
 
 \subsection{Returns}{
-\code{character} string or file path assigned to this \code{ContentBlock}.
+object stored in a \code{private$content} field
 }
 \subsection{Examples}{
 \if{html}{\out{<div class="r example copy">}}
diff --git a/man/FileBlock.Rd b/man/FileBlock.Rd
index a770cf4c..6c83ef45 100644
--- a/man/FileBlock.Rd
+++ b/man/FileBlock.Rd
@@ -47,7 +47,6 @@ block$to_list(tempdir())
 <details open><summary>Inherited methods</summary>
 <ul>
 <li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="get_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-get_content'><code>teal.reporter::ContentBlock$get_content()</code></a></span></li>
-<li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="initialize"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-initialize'><code>teal.reporter::ContentBlock$initialize()</code></a></span></li>
 <li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="set_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-set_content'><code>teal.reporter::ContentBlock$set_content()</code></a></span></li>
 </ul>
 </details>
diff --git a/man/HTMLBlock.Rd b/man/HTMLBlock.Rd
new file mode 100644
index 00000000..971bd698
--- /dev/null
+++ b/man/HTMLBlock.Rd
@@ -0,0 +1,147 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/HTMLBlock.R
+\docType{class}
+\name{HTMLBlock}
+\alias{HTMLBlock}
+\title{\code{HTMLBlock}}
+\description{
+Specialized \code{FileBlock} for managing HTML content in reports.
+It's designed to handle various HTML content, and render the report as HTML,
+however \code{htmlwidgets} objects can also be rendered to static document-ready format.
+}
+\examples{
+
+## ------------------------------------------------
+## Method `HTMLBlock$from_list`
+## ------------------------------------------------
+
+HTMLBlock <- getFromNamespace("HTMLBlock", "teal.reporter")
+block <- HTMLBlock$new()
+block$from_list(list(content = shiny::tags$div("test")))
+
+
+## ------------------------------------------------
+## Method `HTMLBlock$to_list`
+## ------------------------------------------------
+
+HTMLBlock <- getFromNamespace("HTMLBlock", "teal.reporter")
+block <- HTMLBlock$new(shiny::tags$div("test"))
+block$to_list()
+
+}
+\keyword{internal}
+\section{Super class}{
+\code{\link[teal.reporter:ContentBlock]{teal.reporter::ContentBlock}} -> \code{HTMLBlock}
+}
+\section{Methods}{
+\subsection{Public methods}{
+\itemize{
+\item \href{#method-HTMLBlock-new}{\code{HTMLBlock$new()}}
+\item \href{#method-HTMLBlock-from_list}{\code{HTMLBlock$from_list()}}
+\item \href{#method-HTMLBlock-to_list}{\code{HTMLBlock$to_list()}}
+\item \href{#method-HTMLBlock-clone}{\code{HTMLBlock$clone()}}
+}
+}
+\if{html}{\out{
+<details open><summary>Inherited methods</summary>
+<ul>
+<li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="get_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-get_content'><code>teal.reporter::ContentBlock$get_content()</code></a></span></li>
+<li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="set_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-set_content'><code>teal.reporter::ContentBlock$set_content()</code></a></span></li>
+</ul>
+</details>
+}}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-HTMLBlock-new"></a>}}
+\if{latex}{\out{\hypertarget{method-HTMLBlock-new}{}}}
+\subsection{Method \code{new()}}{
+Initialize a \code{HTMLBlock} object.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{HTMLBlock$new(content)}\if{html}{\out{</div>}}
+}
+
+\subsection{Arguments}{
+\if{html}{\out{<div class="arguments">}}
+\describe{
+\item{\code{content}}{An object that can be rendered as a HTML content assigned to
+this \code{HTMLBlock}}
+}
+\if{html}{\out{</div>}}
+}
+\subsection{Returns}{
+Object of class \code{HTMLBlock}, invisibly.
+}
+}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-HTMLBlock-from_list"></a>}}
+\if{latex}{\out{\hypertarget{method-HTMLBlock-from_list}{}}}
+\subsection{Method \code{from_list()}}{
+Create the \code{HTMLBlock} from a list.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{HTMLBlock$from_list(x)}\if{html}{\out{</div>}}
+}
+
+\subsection{Arguments}{
+\if{html}{\out{<div class="arguments">}}
+\describe{
+\item{\code{x}}{(\verb{named list}) with a single field \code{content} containing \code{shiny.tag},
+\code{shiny.tag.list} or \code{htmlwidget}.}
+}
+\if{html}{\out{</div>}}
+}
+\subsection{Returns}{
+\code{self}, invisibly.
+}
+\subsection{Examples}{
+\if{html}{\out{<div class="r example copy">}}
+\preformatted{HTMLBlock <- getFromNamespace("HTMLBlock", "teal.reporter")
+block <- HTMLBlock$new()
+block$from_list(list(content = shiny::tags$div("test")))
+
+}
+\if{html}{\out{</div>}}
+
+}
+
+}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-HTMLBlock-to_list"></a>}}
+\if{latex}{\out{\hypertarget{method-HTMLBlock-to_list}{}}}
+\subsection{Method \code{to_list()}}{
+Convert the \code{HTMLBlock} to a list.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{HTMLBlock$to_list()}\if{html}{\out{</div>}}
+}
+
+\subsection{Returns}{
+\verb{named list} with a text and style.
+}
+\subsection{Examples}{
+\if{html}{\out{<div class="r example copy">}}
+\preformatted{HTMLBlock <- getFromNamespace("HTMLBlock", "teal.reporter")
+block <- HTMLBlock$new(shiny::tags$div("test"))
+block$to_list()
+
+}
+\if{html}{\out{</div>}}
+
+}
+
+}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-HTMLBlock-clone"></a>}}
+\if{latex}{\out{\hypertarget{method-HTMLBlock-clone}{}}}
+\subsection{Method \code{clone()}}{
+The objects of this class are cloneable with this method.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{HTMLBlock$clone(deep = FALSE)}\if{html}{\out{</div>}}
+}
+
+\subsection{Arguments}{
+\if{html}{\out{<div class="arguments">}}
+\describe{
+\item{\code{deep}}{Whether to make a deep clone.}
+}
+\if{html}{\out{</div>}}
+}
+}
+}
diff --git a/man/RcodeBlock.Rd b/man/RcodeBlock.Rd
index 3e5198de..8c106843 100644
--- a/man/RcodeBlock.Rd
+++ b/man/RcodeBlock.Rd
@@ -17,6 +17,15 @@ RcodeBlock <- getFromNamespace("RcodeBlock", "teal.reporter")
 block <- RcodeBlock$new()
 
 
+## ------------------------------------------------
+## Method `RcodeBlock$set_content`
+## ------------------------------------------------
+
+RcodeBlock <- getFromNamespace("RcodeBlock", "teal.reporter")
+block <- RcodeBlock$new()
+block$set_content("a <- 1")
+
+
 ## ------------------------------------------------
 ## Method `RcodeBlock$set_params`
 ## ------------------------------------------------
@@ -70,6 +79,7 @@ block$to_list()
 \subsection{Public methods}{
 \itemize{
 \item \href{#method-RcodeBlock-new}{\code{RcodeBlock$new()}}
+\item \href{#method-RcodeBlock-set_content}{\code{RcodeBlock$set_content()}}
 \item \href{#method-RcodeBlock-set_params}{\code{RcodeBlock$set_params()}}
 \item \href{#method-RcodeBlock-get_params}{\code{RcodeBlock$get_params()}}
 \item \href{#method-RcodeBlock-get_available_params}{\code{RcodeBlock$get_available_params()}}
@@ -82,7 +92,6 @@ block$to_list()
 <details open><summary>Inherited methods</summary>
 <ul>
 <li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="get_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-get_content'><code>teal.reporter::ContentBlock$get_content()</code></a></span></li>
-<li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="set_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-set_content'><code>teal.reporter::ContentBlock$set_content()</code></a></span></li>
 </ul>
 </details>
 }}
@@ -121,6 +130,37 @@ block <- RcodeBlock$new()
 
 }
 
+}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-RcodeBlock-set_content"></a>}}
+\if{latex}{\out{\hypertarget{method-RcodeBlock-set_content}{}}}
+\subsection{Method \code{set_content()}}{
+Sets content of this \code{RcodeBlock}.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{RcodeBlock$set_content(content)}\if{html}{\out{</div>}}
+}
+
+\subsection{Arguments}{
+\if{html}{\out{<div class="arguments">}}
+\describe{
+\item{\code{content}}{(\code{any}) R object}
+}
+\if{html}{\out{</div>}}
+}
+\subsection{Returns}{
+\code{self}, invisibly.
+}
+\subsection{Examples}{
+\if{html}{\out{<div class="r example copy">}}
+\preformatted{RcodeBlock <- getFromNamespace("RcodeBlock", "teal.reporter")
+block <- RcodeBlock$new()
+block$set_content("a <- 1")
+
+}
+\if{html}{\out{</div>}}
+
+}
+
 }
 \if{html}{\out{<hr>}}
 \if{html}{\out{<a id="method-RcodeBlock-set_params"></a>}}
diff --git a/man/ReportCard.Rd b/man/ReportCard.Rd
index 9a910a28..2e3b41e0 100644
--- a/man/ReportCard.Rd
+++ b/man/ReportCard.Rd
@@ -68,6 +68,13 @@ card <- ReportCard$new()
 card <- ReportCard$new()$append_table(iris)
 
 
+## ------------------------------------------------
+## Method `ReportCard$append_html`
+## ------------------------------------------------
+
+card <- ReportCard$new()$append_html(shiny::div("HTML Content"))
+
+
 ## ------------------------------------------------
 ## Method `ReportCard$append_text`
 ## ------------------------------------------------
@@ -126,6 +133,7 @@ ReportCard$new()$set_name("NAME")$get_name()
 \itemize{
 \item \href{#method-ReportCard-new}{\code{ReportCard$new()}}
 \item \href{#method-ReportCard-append_table}{\code{ReportCard$append_table()}}
+\item \href{#method-ReportCard-append_html}{\code{ReportCard$append_html()}}
 \item \href{#method-ReportCard-append_plot}{\code{ReportCard$append_plot()}}
 \item \href{#method-ReportCard-append_text}{\code{ReportCard$append_text()}}
 \item \href{#method-ReportCard-append_rcode}{\code{ReportCard$append_rcode()}}
@@ -192,6 +200,35 @@ that can be coerced into a table.}
 
 }
 
+}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-ReportCard-append_html"></a>}}
+\if{latex}{\out{\hypertarget{method-ReportCard-append_html}{}}}
+\subsection{Method \code{append_html()}}{
+Appends a html content to this \code{ReportCard}.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{ReportCard$append_html(content)}\if{html}{\out{</div>}}
+}
+
+\subsection{Arguments}{
+\if{html}{\out{<div class="arguments">}}
+\describe{
+\item{\code{content}}{An object that can be rendered as a HTML content.}
+}
+\if{html}{\out{</div>}}
+}
+\subsection{Returns}{
+\code{self}, invisibly.
+}
+\subsection{Examples}{
+\if{html}{\out{<div class="r example copy">}}
+\preformatted{card <- ReportCard$new()$append_html(shiny::div("HTML Content"))
+
+}
+\if{html}{\out{</div>}}
+
+}
+
 }
 \if{html}{\out{<hr>}}
 \if{html}{\out{<a id="method-ReportCard-append_plot"></a>}}
diff --git a/man/TextBlock.Rd b/man/TextBlock.Rd
index fd091681..b16b3ba5 100644
--- a/man/TextBlock.Rd
+++ b/man/TextBlock.Rd
@@ -19,6 +19,15 @@ TextBlock <- getFromNamespace("TextBlock", "teal.reporter")
 block <- TextBlock$new()
 
 
+## ------------------------------------------------
+## Method `TextBlock$set_content`
+## ------------------------------------------------
+
+ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
+block <- ContentBlock$new()
+block$set_content("Base64 encoded picture")
+
+
 ## ------------------------------------------------
 ## Method `TextBlock$set_style`
 ## ------------------------------------------------
@@ -72,6 +81,7 @@ block$to_list()
 \subsection{Public methods}{
 \itemize{
 \item \href{#method-TextBlock-new}{\code{TextBlock$new()}}
+\item \href{#method-TextBlock-set_content}{\code{TextBlock$set_content()}}
 \item \href{#method-TextBlock-set_style}{\code{TextBlock$set_style()}}
 \item \href{#method-TextBlock-get_style}{\code{TextBlock$get_style()}}
 \item \href{#method-TextBlock-get_available_styles}{\code{TextBlock$get_available_styles()}}
@@ -84,7 +94,6 @@ block$to_list()
 <details open><summary>Inherited methods</summary>
 <ul>
 <li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="get_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-get_content'><code>teal.reporter::ContentBlock$get_content()</code></a></span></li>
-<li><span class="pkg-link" data-pkg="teal.reporter" data-topic="ContentBlock" data-id="set_content"><a href='../../teal.reporter/html/ContentBlock.html#method-ContentBlock-set_content'><code>teal.reporter::ContentBlock$set_content()</code></a></span></li>
 </ul>
 </details>
 }}
@@ -123,6 +132,37 @@ block <- TextBlock$new()
 
 }
 
+}
+\if{html}{\out{<hr>}}
+\if{html}{\out{<a id="method-TextBlock-set_content"></a>}}
+\if{latex}{\out{\hypertarget{method-TextBlock-set_content}{}}}
+\subsection{Method \code{set_content()}}{
+Sets content of this \code{TextBlock}.
+\subsection{Usage}{
+\if{html}{\out{<div class="r">}}\preformatted{TextBlock$set_content(content)}\if{html}{\out{</div>}}
+}
+
+\subsection{Arguments}{
+\if{html}{\out{<div class="arguments">}}
+\describe{
+\item{\code{content}}{(\code{any}) R object}
+}
+\if{html}{\out{</div>}}
+}
+\subsection{Returns}{
+\code{self}, invisibly.
+}
+\subsection{Examples}{
+\if{html}{\out{<div class="r example copy">}}
+\preformatted{ContentBlock <- getFromNamespace("ContentBlock", "teal.reporter")
+block <- ContentBlock$new()
+block$set_content("Base64 encoded picture")
+
+}
+\if{html}{\out{</div>}}
+
+}
+
 }
 \if{html}{\out{<hr>}}
 \if{html}{\out{<a id="method-TextBlock-set_style"></a>}}
diff --git a/tests/testthat/test-ContentBlock.R b/tests/testthat/test-ContentBlock.R
index 141687e7..0db7e19f 100644
--- a/tests/testthat/test-ContentBlock.R
+++ b/tests/testthat/test-ContentBlock.R
@@ -11,9 +11,9 @@ testthat::test_that("set_content accepts a character object", {
   testthat::expect_no_error(block$set_content("test"))
 })
 
-testthat::test_that("set_content asserts the argument is character", {
+testthat::test_that("set_content accepts a list object", {
   block <- ContentBlock$new()
-  testthat::expect_error(block$set_content(7), regexp = "Must be of type 'character'")
+  testthat::expect_no_error(block$set_content(list("a")))
 })
 
 testthat::test_that("set_content returns the ContentBlock object", {
@@ -21,8 +21,8 @@ testthat::test_that("set_content returns the ContentBlock object", {
   testthat::expect_identical(block$set_content("test"), block)
 })
 
-testthat::test_that("get_content returns character(0) on a newly initialized ContentBlock", {
-  testthat::expect_equal(ContentBlock$new()$get_content(), character(0))
+testthat::test_that("get_content returns NULL on a newly initialized ContentBlock", {
+  testthat::expect_equal(ContentBlock$new()$get_content(), NULL)
 })
 
 testthat::test_that("The deep copy constructor copies the content file to a new file", {
diff --git a/tests/testthat/test-HTMLBlock.R b/tests/testthat/test-HTMLBlock.R
new file mode 100644
index 00000000..8ec13044
--- /dev/null
+++ b/tests/testthat/test-HTMLBlock.R
@@ -0,0 +1,40 @@
+testthat::test_that("HTMLBlock object can be created", {
+  testthat::expect_no_error(HTMLBlock$new())
+})
+
+testthat::test_that("new returns an object of type HTMLBlock", {
+  testthat::expect_true(inherits(HTMLBlock$new(), "HTMLBlock"))
+})
+
+
+testthat::test_that("new accepts a shiny.tag", {
+  testthat::expect_no_error(HTMLBlock$new(shiny::tags$div()))
+})
+
+testthat::test_that("new accepts a shiny.tag.list", {
+  testthat::expect_no_error(HTMLBlock$new(shiny::tagList()))
+})
+
+testthat::test_that("new doesn't accept character", {
+  testthat::expect_error(HTMLBlock$new("test"), "'shiny.tag'/'shiny.tag.list'")
+})
+
+testthat::test_that("get_content returns a html content asis", {
+  content <- shiny::tags$div()
+  obj <- HTMLBlock$new(content)
+  testthat::expect_identical(obj$get_content(), content)
+})
+
+testthat::test_that("to_list returns a list containing a content (asis)", {
+  content <- shiny::tags$div()
+  obj <- HTMLBlock$new(content)
+  out <- obj$to_list()
+  testthat::expect_identical(out, list(content = content))
+})
+
+testthat::test_that("from_list creates a HTMLBlock", {
+  list <- list(content = shiny::tags$div())
+  obj <- HTMLBlock$new()
+  obj$from_list(list)
+  testthat::expect_identical(obj$get_content(), list$content)
+})
diff --git a/tests/testthat/test-RcodeBlock.R b/tests/testthat/test-RcodeBlock.R
index 6066d237..0b4a3503 100644
--- a/tests/testthat/test-RcodeBlock.R
+++ b/tests/testthat/test-RcodeBlock.R
@@ -13,7 +13,7 @@ testthat::test_that("set_content accepts a string", {
 
 testthat::test_that("set_content asserts the argument is a string", {
   block <- RcodeBlock$new()
-  testthat::expect_error(block$set_content(7), regexp = "Must be of type 'character'")
+  testthat::expect_error(block$set_content(7), regexp = "Must be of type 'string'")
 })
 
 testthat::test_that("set_content returns the RcodeBlock object", {
diff --git a/tests/testthat/test-Renderer.R b/tests/testthat/test-Renderer.R
index cf3ece71..6df7141b 100644
--- a/tests/testthat/test-Renderer.R
+++ b/tests/testthat/test-Renderer.R
@@ -12,19 +12,20 @@ text_block1 <- TextBlock$new()$set_content("text")$set_style("header2")
 text_block2 <- TextBlock$new()$set_content("text")
 png_path <- system.file("img", "Rlogo.png", package = "png")
 picture_block <- PictureBlock$new()$set_content(ggplot2::ggplot(iris))
+html_block <- HTMLBlock$new(shiny::tags$div("test"))
 # https://github.com/davidgohel/flextable/issues/600
 withr::with_options(
   opts_partial_match_old,
   table_block <- TableBlock$new()$set_content(iris)
 )
 newpage_block <- NewpageBlock$new()
-blocks <- list(text_block1, text_block2, picture_block, table_block, newpage_block)
+blocks <- list(text_block1, text_block2, picture_block, table_block, newpage_block, html_block)
 
 testthat::test_that("renderRmd asserts the argument is a list of TextBlocks/PictureBlock/NewpageBlock/TableBlock", {
   renderer <- Renderer$new()
   testthat::expect_error(
     renderer$renderRmd(append(blocks, "STH")),
-    regexp = "May only contain the following types: \\{TextBlock,PictureBlock,NewpageBlock,TableBlock,RcodeBlock\\}"
+    regexp = "May only contain the following types: \\{TextBlock,PictureBlock,NewpageBlock,TableBlock,RcodeBlock,HTMLBlock\\}" # nolint line_length
   )
 })
 
diff --git a/tests/testthat/test-ReportCard.R b/tests/testthat/test-ReportCard.R
index afd5730c..8aa9b422 100644
--- a/tests/testthat/test-ReportCard.R
+++ b/tests/testthat/test-ReportCard.R
@@ -175,6 +175,7 @@ card$append_text("Header 2 text", "header2")
 card$append_text("A paragraph of default text", "header2")
 card$append_rcode(rcode)
 card$append_plot(eval(str2lang(rcode)))
+card$append_html(shiny::tags$div("test"))
 
 picture_filename <- basename(card$get_content()[[4]]$get_content())
 temp_dir <- file.path(tempdir(), "test")
@@ -187,7 +188,8 @@ testthat::test_that("to_list internally triggers to_list on each Block", {
       TextBlock = list(text = "Header 2 text", style = "header2"),
       TextBlock = list(text = "A paragraph of default text", style = "header2"),
       RcodeBlock = list(text = rcode, params = list()),
-      PictureBlock = list(basename = picture_filename)
+      PictureBlock = list(basename = picture_filename),
+      HTMLBlock = list(content = shiny::tags$div("test"))
     ), metadata = list(), name = character(0))
   )
   testthat::expect_true(picture_filename %in% list.files(temp_dir))
@@ -199,12 +201,13 @@ testthat::test_that("from_list", {
       TextBlock = list(text = "Header 2 text", style = "header2"),
       TextBlock = list(text = "A paragraph of default text", style = "header2"),
       RcodeBlock = list(text = rcode, params = list()),
-      PictureBlock = list(basename = picture_filename)
+      PictureBlock = list(basename = picture_filename),
+      HTMLBlock = list(content = shiny::tags$div("test"))
     ), metadata = list()),
     temp_dir
   )
   testthat::expect_true(inherits(cardf, "ReportCard"))
-  testthat::expect_length(cardf$get_content(), 4L)
+  testthat::expect_length(cardf$get_content(), 5L)
 })
 
 unlink(temp_dir, recursive = TRUE)
diff --git a/tests/testthat/test-TextBlock.R b/tests/testthat/test-TextBlock.R
index faa30b04..a01fe0c0 100644
--- a/tests/testthat/test-TextBlock.R
+++ b/tests/testthat/test-TextBlock.R
@@ -13,7 +13,7 @@ testthat::test_that("set_content accepts a string", {
 
 testthat::test_that("set_content asserts the argument is a string", {
   block <- TextBlock$new()
-  testthat::expect_error(block$set_content(7), regexp = "Must be of type 'character'")
+  testthat::expect_error(block$set_content(7), regexp = "Must be of type 'string'")
 })
 
 testthat::test_that("set_content returns the TextBlock object", {