Adding a company Logo to ShinyDashboard header

I've been working with a bit of a hack for this, (and I know you didn't ask for it, but here's a clickable logo while we're at it):

library(shiny)
library(shinydashboard)

dbHeader <- dashboardHeader()
dbHeader$children[[2]]$children <-  tags$a(href='http://mycompanyishere.com',
                                           tags$img(src='logo.png',height='60',width='200'))

dashboardPage(
       dbHeader,
       dashboardSidebar(),
       dashboardBody()
)

So this nests a shiny.tag inside the header. The second slot in this particular shiny object is the logo slot (You'll need a 'logo.png' in your /www/ folder in the app directory)

EDIT:

I just checked, and as of right now, this hack should no longer be necessary, you can insert the html directly from the dashboardHeader function via the title= parameter, (Before, that parameter was enforcing text only),

I think the answer might still be useful as a method to modify existing shiny functions where things ARE hardcoded in though.

Here's the method now:

dashboardPage(
    dashboardHeader(title = tags$a(href='http://mycompanyishere.com',
                                    tags$img(src='logo.png')))

or, adding a little more magic to the logo (I also use my logo as a loading bar):

# Takes a location 'href', an image location 'src', a loading gif 'loadingsrc'
# height, width and alt text, and produces a loading logo that activates while
# Shiny is busy
loadingLogo <- function(href, src, loadingsrc, height = NULL, width = NULL, alt = NULL) {
  tagList(
    tags$head(
      tags$script(
        "setInterval(function(){
                     if ($('html').attr('class')=='shiny-busy') {
                     $('div.busy').show();
                     $('div.notbusy').hide();
                     } else {
                     $('div.busy').hide();
                     $('div.notbusy').show();
           }
         },100)")
  ),
  tags$a(href=href,
         div(class = "busy",  
             img(src=loadingsrc,height = height, width = width, alt = alt)),
         div(class = 'notbusy',
             img(src = src, height = height, width = width, alt = alt))
   )
  )
}

dashboardBody(
  dashboardHeader(title = loadingLogo('http://mycompanyishere.com',
                                      'logo.png',
                                      'loader.gif'),
  dashboardSidebar(),
  dashboardBody()
)

Here's my hack (put your logo, as has been mentioned before, into a www subdirectory of your app directory).
Because dashboardHeader() expects a tag element of type li and class dropdown, we can pass such elements instead of dropdownMenus:

library(shiny)
library(shinydashboard)

dbHeader <- dashboardHeader(title = "My Dashboard",
                            tags$li(a(href = 'http://shinyapps.company.com',
                                      icon("power-off"),
                                      title = "Back to Apps Home"),
                                    class = "dropdown"),
                            tags$li(a(href = 'http://www.company.com',
                                      img(src = 'company_logo.png',
                                          title = "Company Home", height = "30px"),
                                      style = "padding-top:10px; padding-bottom:10px;"),
                                    class = "dropdown"))

server <- function(input, output) {}

shinyApp(
    ui = dashboardPage(
        dbHeader,
        dashboardSidebar(),
        dashboardBody()
    ),
    server = server
)