Add local cache for fetched body

1 files changed, 127 insertions, 59 deletions

diff --git a/cmd/cetus/main.go b/cmd/cetus/main.go
index 7d4ebc8..fa53e9a 100644
--- a/cmd/cetus/main.go
+++ b/cmd/cetus/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"io/ioutil"
 	"math/rand"
 	"os"
 	"time"
@@ -140,12 +141,11 @@ func getCacheDir() string {
 }
 
 func execAPOD() {
-	// reqInfo holds all the parameters that needs to be
-	// sent with the request. GetJson() will pack apiKey &
-	// date in params map before sending it to another
-	// function. Adding params here will not change the
-	// behaviour of the function, changes have to be made
-	// in GetJson() too.
+	// reqInfo holds all the parameters that needs to be sent with
+	// the request. GetJson() will pack apiKey & date in params
+	// map before sending it to another function. Adding params
+	// here will not change the behaviour of the function, changes
+	// have to be made in GetJson() too.
 	reqInfo := make(map[string]string)
 	reqInfo["api"] = string(*apodAPI)
 	reqInfo["apiKey"] = string(*apodKey)
@@ -155,8 +155,28 @@ func execAPOD() {
 		reqInfo["date"] = apod.RandDate()
 	}
 
-	body, err := apod.GetJson(reqInfo)
-	chkErr(err)
+	cacheDir := fmt.Sprintf("%s/%s", getCacheDir(), "apod")
+	os.MkdirAll(cacheDir, os.ModePerm)
+
+	// Check if the file is available locally, if it is then don't
+	// download it again and get it from disk
+	var body string
+	file := fmt.Sprintf("%s/%s", cacheDir, reqInfo["date"])
+	if _, err := os.Stat(file); err == nil {
+		data, err := ioutil.ReadFile(file)
+		chkErr(err)
+		body = string(data)
+	} else if os.IsNotExist(err) {
+		body, err = apod.GetJson(reqInfo)
+		chkErr(err)
+
+		// Write body to the cache so that it can be read
+		// later
+		err = ioutil.WriteFile(file, []byte(body), 0644)
+		chkErr(err)
+	} else {
+		chkErr(err)
+	}
 
 	if *apodDump {
 		fmt.Printf(body)
@@ -164,34 +184,32 @@ func execAPOD() {
 	}
 
 	res := apod.Res{}
-	err = apod.UnmarshalJson(&res, body)
+	err := apod.UnmarshalJson(&res, body)
 	chkErr(err)
 
-	// res.Msg will be returned when there is error on
-	// user input or the api server.
+	// res.Msg will be returned when there is error on user input
+	// or the api server.
 	if len(res.Msg) != 0 {
 		fmt.Printf("Message: %s", res.Msg)
 		os.Exit(1)
 	}
 
-	// If path-only is passed then it will only print the
-	// path, even if quiet is passed. If the user wants
-	// the program to be quiet then path-only shouldn't be
-	// passed. If path-only is not passed & quiet is also
-	// not passed then print the response.
+	// If path-only is passed then it will only print the path,
+	// even if quiet is passed. If the user wants the program to
+	// be quiet then path-only shouldn't be passed. If path-only
+	// is not passed & quiet is also not passed then print the
+	// response.
 	//
-	// Path is only printed when the media type is an
-	// image because res.HDURL is empty on non image media
-	// type.
+	// Path is only printed when the media type is an image
+	// because res.HDURL is empty on non image media type.
 	if *apodPathOnly {
 		fmt.Println(res.HDURL)
 	} else if !*apodQuiet {
 		apod.Print(res)
 	}
 
-	// Proceed only if the command was set because if it
-	// was fetch then it's already finished & should exit
-	// now.
+	// Proceed only if the command was set because if it was fetch
+	// then it's already finished & should exit now.
 	if os.Args[1] == "fetch" {
 		os.Exit(0)
 	}
@@ -203,30 +221,29 @@ func execAPOD() {
 	if res.MediaType != "image" {
 		os.Exit(0)
 	}
-	cacheDir := fmt.Sprintf("%s/%s", getCacheDir(), "apod")
-	os.MkdirAll(cacheDir, os.ModePerm)
-	file := fmt.Sprintf("%s/%s", cacheDir, reqInfo["date"])
+	imgCacheDir := fmt.Sprintf("%s/%s", cacheDir, "background")
+	os.MkdirAll(imgCacheDir, os.ModePerm)
+	imgFile := fmt.Sprintf("%s/%s", imgCacheDir, reqInfo["date"])
 
 	// Check if the file is available locally, if it is
 	// then don't download it again and set it from disk
-	if _, err := os.Stat(file); os.IsNotExist(err) {
-		err = background.Download(file, res.HDURL)
+	if _, err := os.Stat(imgFile); os.IsNotExist(err) {
+		err = background.Download(imgFile, res.HDURL)
 		chkErr(err)
 	} else {
 		chkErr(err)
 	}
 
-	err = background.Set(file)
+	err = background.Set(imgFile)
 	chkErr(err)
 }
 
 func execBPOD() {
-	// reqInfo holds all the parameters that needs to be
-	// sent with the request. GetJson() will pack apiKey &
-	// date in params map before sending it to another
-	// function. Adding params here will not change the
-	// behaviour of the function, changes have to be made
-	// in GetJson() too.
+	// reqInfo holds all the parameters that needs to be sent with
+	// the request. GetJson() will pack apiKey & date in params
+	// map before sending it to another function. Adding params
+	// here will not change the behaviour of the function, changes
+	// have to be made in GetJson() too.
 	reqInfo := make(map[string]string)
 	reqInfo["api"] = string(*bpodAPI)
 
@@ -234,14 +251,54 @@ func execBPOD() {
 		reqInfo["random"] = "true"
 	}
 
-	body, err := bpod.GetJson(reqInfo)
-	chkErr(err)
+	cacheDir := fmt.Sprintf("%s/%s", getCacheDir(), "bpod")
+	os.MkdirAll(cacheDir, os.ModePerm)
 
-	if *bpodDump {
-		fmt.Printf(body)
-		os.Exit(0)
+	// Check if the file is available locally, if it is then don't
+	// download it again and get it from disk.
+	//
+	// We don't know the bpod date because that will be there in
+	// response & we can't read the response without requesting
+	// it. So this will assume the bpod date to be today's date if
+	// *bpodRand is not set true. If *bpodRand is set true then we
+	// can't assume the date. Also this way too it can cause error
+	// if our assumed date doesn't matches date at the server.
+	var body string
+	var file string
+	var err error
+
+	if !*bpodRand {
+		// If not *bpodRand and the file exists then read from
+		// disk, if the file doesn't exist then get it and
+		// save it to disk.
+		file = fmt.Sprintf("%s/%s", cacheDir, time.Now().UTC().Format("2006-01-02"))
+		if _, err := os.Stat(file); err == nil {
+			data, err := ioutil.ReadFile(file)
+			chkErr(err)
+			body = string(data)
+		} else if os.IsNotExist(err) {
+			body, err = bpod.GetJson(reqInfo)
+			chkErr(err)
+
+			// Write body to the cache so that it can be
+			// read later
+			err = ioutil.WriteFile(file, []byte(body), 0644)
+			chkErr(err)
+		} else {
+			chkErr(err)
+		}
+	} else {
+		// If *bpodRand then get the file and save it to disk
+		// after unmarshal because we don't know the file name
+		// yet
+		body, err = bpod.GetJson(reqInfo)
+		chkErr(err)
 	}
 
+	// Unmarshal before dump because otherwise if we come across
+	// the date for the first time then it would just dump and
+	// exit without saving it to cache. This way we first save it
+	// to cache if *bpodRand is true.
 	res, err := bpod.UnmarshalJson(body)
 	chkErr(err)
 
@@ -251,24 +308,35 @@ func execBPOD() {
 	chkErr(err)
 	res.StartDate = dt.Format("2006-01-02")
 
-	// If path-only is passed then it will only print the
-	// path, even if quiet is passed. If the user wants
-	// the program to be quiet then path-only shouldn't be
-	// passed. If path-only is not passed & quiet is also
-	// not passed then print the response.
+	file = fmt.Sprintf("%s/%s", cacheDir, res.StartDate)
+	if *bpodRand {
+		// Write body to the cache so that it can be read
+		// later
+		err = ioutil.WriteFile(file, []byte(body), 0644)
+		chkErr(err)
+	}
+
+	if *bpodDump {
+		fmt.Printf(body)
+		os.Exit(0)
+	}
+
+	// If path-only is passed then it will only print the path,
+	// even if quiet is passed. If the user wants the program to
+	// be quiet then path-only shouldn't be passed. If path-only
+	// is not passed & quiet is also not passed then print the
+	// response.
 	//
-	// Path is only printed when the media type is an
-	// image because res.HDURL is empty on non image media
-	// type.
+	// Path is only printed when the media type is an image
+	// because res.HDURL is empty on non image media type.
 	if *bpodPathOnly {
 		fmt.Println(res.Url)
 	} else if !*bpodQuiet {
 		bpod.Print(res)
 	}
 
-	// Proceed only if the command was set because if it
-	// was fetch then it's already finished & should exit
-	// now.
+	// Proceed only if the command was set because if it was fetch
+	// then it's already finished & should exit now.
 	if os.Args[1] == "fetch" {
 		os.Exit(0)
 	}
@@ -277,20 +345,20 @@ func execBPOD() {
 	// First it downloads the image to the cache directory and
 	// then tries to set it with feh. If the download fails then
 	// it exits with a non-zero exit code.
-	cacheDir := fmt.Sprintf("%s/%s", getCacheDir(), "bpod")
-	os.MkdirAll(cacheDir, os.ModePerm)
-	file := fmt.Sprintf("%s/%s", cacheDir, res.StartDate)
-
-	// Check if the file is available locally, if it is
-	// then don't download it again and set it from disk
-	if _, err := os.Stat(file); os.IsNotExist(err) {
-		err = background.Download(file, res.Url)
+	imgCacheDir := fmt.Sprintf("%s/%s", cacheDir, "background")
+	os.MkdirAll(imgCacheDir, os.ModePerm)
+	imgFile := fmt.Sprintf("%s/%s", imgCacheDir, res.StartDate)
+
+	// Check if the file is available locally, if it is then don't
+	// download it again and set it from disk
+	if _, err := os.Stat(imgFile); os.IsNotExist(err) {
+		err = background.Download(imgFile, res.Url)
 		chkErr(err)
 	} else {
 		chkErr(err)
 	}
 
-	err = background.Set(file)
+	err = background.Set(imgFile)
 	chkErr(err)
 }