lastfmApp_server.R

#server.r

library(shiny)

shinyServer(function(input, output) {
  
  
  library(rjson)
  library(ggplot2)
  library(grid)
  
  #create functions to pull down data from api
  
  topArtists<-function(limit=100){
    
    eval(parse(text=paste0("search<-fromJSON(file=\"http://ws.audioscrobbler.com/2.0/?method=chart.gettopartists&api_key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx&format=json&limit=", limit, "\")")))
    
    topArtists<-data.frame(position=NULL, artist=NULL, playcount=NULL, listeners=NULL)
    for (i in c(1:limit)){
      temp<-data.frame(
        position=i,
        artist=search$artist$artist[[i]]$name,
        playcount=search$artist$artist[[i]]$playcount,
        listeners=search$artist$artist[[i]]$listeners
      )
      topArtists<-rbind(topArtists, temp)
    }
    return(topArtists)
  }
  
  topTracks<-function(limit=5){

    eval(parse(text=paste0("search<-fromJSON(file=\"http://ws.audioscrobbler.com/2.0/?method=chart.gettoptracks&api_key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx&format=json&limit=", limit, "\")")))

    topTracks<-data.frame(position=NULL, track=NULL, artist=NULL, playcount=NULL, listeners=NULL, duration=NULL)
    for (i in c(1:limit)){
      temp<-data.frame(
        position=i,
        track=search$tracks$track[[i]]$name,
        artist=search$tracks$track[[i]]$artist$name,
        playcount=search$tracks$track[[i]]$playcount,
        listeners=search$tracks$track[[i]]$listeners,
        duration=search$tracks$track[[i]]$duration
      )
      topTracks<-rbind(topTracks, temp)
    }
    return(topTracks)
  }
  
  #run functions to pull data
  
  topArtistsData<-topArtists(100)
  topTracksData<-topTracks(100)
  
  #produce table and plots for top artists
  
  output$artistData<-renderTable({
      topArtistsData[1:input$obs,2:4]
      })
  
  output$artistListeners<-renderPlot({
    data<-topArtistsData[1:input$obs,2:4]
    ggplot(data, aes(x=artist, y=as.numeric(as.character(listeners)))) + 
      geom_bar(stat="identity", fill="red", colour="black") +
      labs(title="Listeners", y="", x="") +
      theme(title=element_text(size=20)) +
      theme(axis.text.x=element_text(angle=90,hjust=1,vjust=0.5, size=21-(0.1*input$obs)), axis.ticks.margin=unit(0,'cm')) +
      theme(axis.text.y=element_text(size=15)) +
      theme(panel.grid = element_blank(), panel.background = element_rect(fill="white"))
      })     
    
  output$artistPlaycount<-renderPlot({
    data<-topArtistsData[1:input$obs,2:4]
    ggplot(data, aes(x=artist, y=as.numeric(as.character(playcount)))) + 
      geom_bar(stat="identity", fill="red", colour="black") +
      labs(title="Plays", y="", x="") +
      theme(title=element_text(size=20)) +
      theme(axis.text.x=element_text(angle=90,hjust=1,vjust=0.5, size=21-(0.1*input$obs)), axis.ticks.margin=unit(0,'cm')) +
      theme(axis.text.y=element_text(size=15)) +
      theme(panel.grid = element_blank(), panel.background = element_rect(fill="white"))
      })  
  
  #produce table and plots for top tracks
  
  output$trackData<-renderTable({
    topTracksData[1:input$obs,2:5]
  })
  
  output$trackListeners<-renderPlot({
    data<-topTracksData[1:input$obs,2:5]
    ggplot(data, aes(x=track, y=as.numeric(as.character(listeners)))) + 
      geom_bar(stat="identity", fill="red", colour="black") +
      labs(title="Listeners", y="", x="") +
      theme(title=element_text(size=20)) +
      theme(axis.text.x=element_text(angle=90,hjust=1,vjust=0.5, size=15-(0.1*input$obs)), axis.ticks.margin=unit(0,'cm')) +
      theme(axis.text.y=element_text(size=15)) +
      theme(panel.grid = element_blank(), panel.background = element_rect(fill="white"))
  })     
  
  output$trackPlaycount<-renderPlot({
    data<-topTracksData[1:input$obs,2:5]
    ggplot(data, aes(x=track, y=as.numeric(as.character(playcount)))) + 
      geom_bar(stat="identity", fill="red", colour="black") +
      labs(title="Plays", y="", x="") +
      theme(title=element_text(size=20)) +
      theme(axis.text.x=element_text(angle=90,hjust=1,vjust=0.5, size=15-(0.1*input$obs)), axis.ticks.margin=unit(0,'cm')) +
      theme(axis.text.y=element_text(size=15)) +
      theme(panel.grid = element_blank(), panel.background = element_rect(fill="white"))
  }) 
  
  
  
  
  
  
  
})