server.r

require(ggplot2)
require(grid)

shinyServer(function(input, output) {

    parameters <- NULL

    processs_follow <- function(input){
        if(input$user_ids != ''){
            paste0('follow=', gsub(' ', '', input$user_ids))    
        } else NULL
    }

    process_track <- function(input){

        track_all <- if(input$track_terms_all != ''){
            gsub(',', ' ', gsub(' ', '', input$track_terms_all))
        }
        track_any <- if(input$track_terms_any != ''){
            gsub(' ', '', input$track_terms_any)
        }
            
        track_words <- NULL
        if(length(track_any) > 0 && length(track_all) > 0){
            track_words <- paste0(track_all, ',', track_any)      

        } else if(length(track_any) > 0){
            track_words <- track_any}
        else if(length(track_all) > 0) track_words <- track_all

        if(length(track_any) + length(track_all) > 0){
            paste0('track=', track_words)
        }else NULL
    }

    process_locations <- function(input){
        if(input$coordinates != ''){
            paste0('locations=', gsub(' ', '', input$coordinates))    
        } else NULL
    }
    output$user_id <- reactiveText(function(){
        require(twitteR)
        
        tmp <- if(input$user_name != ''){
            getUser(input$user_name)$id
        }
        if(!is.null(tmp)) tmp else 'user not found'
      
    })
    output$bounding_box <- reactiveText(function(){
    
        paste0(c(input$lon_range[1], input$lat_range[1],
         input$lon_range[2], input$lat_range[2]), collapse = ',')
        
    })
    output$query_string <- reactiveText(function(){
        url <- switch(
            input$endpoint,
            'Advanced' = 'https://stream.twitter.com/1.1/statuses/filter.json?',
            'Simple' = 'https://stream.twitter.com/1.1/statuses/sample.json?')

        if(input$stall_warnings) parameters <- c(parameters, 'stall_warnings=true')
        if(input$delimited)      parameters <- c(parameters, 'delimited=length')

        follow <- processs_follow(input)
        track  <- process_track(input) 
        locations <- process_locations(input)

        url <- paste0(url, paste0(c(follow, track, locations, parameters), collapse = '&'))

        return(url)
    })
    
    output$map <- reactivePlot(function(){
        require(ggplot2)
        
        map <- map_data('world') 
        map <- cbind(map, 
            c(map[,2] > input$lat_range[1] & 
            map[,2] < input$lat_range[2] &
            map[,1] > input$lon_range[1] & 
            map[,1] < input$lon_range[2]))

        names(map)[length(names(map))] <- 'colour'
        
        plot(ggplot(data = map, legend=FALSE) + geom_polygon(
            aes(x=long, y=lat, group=group, colour = colour), 
            size = 0.1, fill = '#A6A6A6') +
            geom_line(data=
                data.frame(x=c(-180, 180), y=rep(input$lat_range[1], 2)), 
                aes(x=x, y=y), linetype=2) +
            geom_line(data=
                data.frame(x=c(-180, 180), y=rep(input$lat_range[2], 2)),
                aes(x=x, y=y), linetype=2) +
            geom_line(data=
                data.frame(x=rep(input$lon_range[1], 2), y=c(-90, 90)), 
              aes(x=x, y=y), linetype=2) +
            geom_line(data=
                data.frame(x=rep(input$lon_range[2], 2), y=c(-90, 90)),
                aes(x=x, y=y), linetype=2) + 
            scale_colour_manual(
                values = c('#B4CDCD', '#37FDFC')) +
            theme(
                axis.line = theme_blank(), 
                axis.text.x = theme_blank(), 
                axis.text.y = theme_blank(),
                axis.ticks = theme_blank(), 
                axis.title.x = theme_blank(), 
                axis.title.y = theme_blank(), 
                panel.background = theme_blank(), 
                panel.border = theme_blank(), 
                panel.grid.major = theme_blank(), 
                panel.grid.minor = theme_blank(), 
                plot.background = theme_blank(),
                legend.position = "none"
            ))
    })
})

ui.r

shinyUI(pageWithSidebar(

    headerPanel('Streaming Search Tool'),

    sidebarPanel( 
        (function(){
            # three buttons to select the twitter endpoint

            wellPanel(radioButtons(
                "endpoint", "Streaming API Endpoint", 
                choices = c("Simple", "Advanced")))
        })(),
        conditionalPanel(
            "input.endpoint == 'Advanced'",
            wellPanel('Lookup User',
                (function(){
                    
                    textInput('user_name' , 'User Name', '')
                    
                })(),
                (function(){
                  
                    verbatimTextOutput('user_id')
                  
                })()
            ),
            wellPanel('Bounding Box',
            plotOutput('map'),
            
            (function(){
                # a slider to pick longitudes    
                
                sliderInput(
                    'lon_range', 'longitude', -180, 180, c(-180, 180), 0.1)
                
            })(),
            (function(){
                # a slider to pick latitudes    
                
                sliderInput(
                    'lat_range', 'latitude', -90, 90, c(-90, 90), 0.1)
            
            })(),
            (function(){
              
                verbatimTextOutput('bounding_box')
              
        })()
        ))    
        
    ),  

    mainPanel('Query',              
        (function(){
            # print the query as it is being formed

            verbatimTextOutput('query_string')
        }
        )(),        
        (function(){
            conditionalPanel(
                "input.endpoint == 'Advanced'", 
                wellPanel('Fields',
                    textInput('user_ids', "User Id's to Follow", ''),    
                    textInput('track_terms_all', "All These Words", ''),
                    textInput('track_terms_any', "Any of These Words", ''),
                    (function(){
                        textInput('coordinates', "Any of These Bounding Boxes", '')
                    })()   
        ))
  	
        })(),
        (function(){
            # adds the 'stall-warnings' option

            checkboxInput(inputId='stall_warnings', 
                label='give warnings if client falls behind?', value=FALSE)

        })(),
        (function(){
            # adds the 'delimited' option

            checkboxInput(inputId='delimited', 
                label='add delimiters to the tweet stream?', value=FALSE)

        })()

    )
))