added script to download and cache users photos

1 files changed, 121 insertions, 0 deletions

diff --git a/utilCacheUserPhotosForDB.tcl b/utilCacheUserPhotosForDB.tcl
new file mode 100755
index 0000000..e0f2813
--- /dev/null
+++ b/utilCacheUserPhotosForDB.tcl
@@ -0,0 +1,121 @@
+#!/bin/sh
+# vim:set ft=tcl: \
+exec tclsh "$0" "$@"
+
+# require Tcl version of at least 8.5 since I use 'ni' and 'in' in expressions for lists
+package require Tcl 8.5
+package require sqlite3
+
+if { $argc < 1 } {	
+	puts {Populates photo cache directory for users from the database}
+	puts {Usage:}
+	puts "  $argv0 database_filename"
+	puts {}
+	puts {Example:}
+	puts "  $argv0  2013_Spring_Phys742"
+	exit
+}
+
+set dbfile [lindex $argv 0] 
+
+source ./GradeBook_lib.tcl
+
+set config_file "./gb_config.tcl"
+if { [file exists $config_file] && ("$config_file" ne "") } {
+	source $config_file
+} else {
+	puts "error: config file {$config_file} does not exist"
+	exit
+}
+
+if { [file exists $dbfile] } {
+	sqlite3 db $dbfile
+} else {
+	puts "error: non existing DB filename {$dbfile}"
+	exit
+}
+
+proc getAllIds {ids_col table_with_ids} {
+	set ids {}
+	set eval_str "SELECT \"$ids_col\"  FROM \"$table_with_ids\""
+	set err [catch {
+		db eval $eval_str v {
+			if { [info exist v($ids_col)] } {	
+				lappend ids $v($ids_col)
+			} 
+		}
+	} errStat ]
+	if { $err } {
+		puts  "the following error happen: $errStat" msg_level_critical
+	} 
+	return $ids
+}
+
+proc cachePhotoForId { IdNum } {
+	# attempt to cache the photo for a given id
+	global GradebookServerConfig
+	set photo_album_base_url $GradebookServerConfig(photo_album_base_url)
+	set photo_album_cache $GradebookServerConfig(photo_album_cache)
+
+	# generate url pointing to a photo of a user with the given IdNum
+	set photo_file "${IdNum}.jpg"
+	set cached_photo_file "$photo_album_cache/${photo_file}"
+	set url "$photo_album_base_url/$photo_file"
+
+	if { [file exists "$cached_photo_file"] } {
+		# file already cached no need to download
+		return
+	}
+	if { ![file exists "$photo_album_cache"] } {
+		# cache directory missing let's make it
+		set errMkDir [catch {
+			file mkdir "$photo_album_cache"
+		} errStat ]
+		if { $errMkDir } {
+			puts  "Error: $errStat"
+			return
+		}
+	}
+	
+	# Download url to cache
+	
+	# below replacing whitespace with %20 and # with %23 in the URL in $target
+	set url [string map {{ } %20 {#} %23 } $url]
+	set command_str exec
+	lappend command_str wget
+	lappend command_str -q
+	lappend command_str -c
+	lappend command_str --output-document=$cached_photo_file
+	lappend command_str $url
+	puts $command_str
+	# TODO: devise some sort of lock mechanism to protect against duplicate downloads
+	set err [catch {eval $command_str} result]
+	if { $err } {
+		puts "Something wrong with download of {$url}"
+		# remove erroneous download file
+		file delete $cached_photo_file
+	} else {
+		puts "Successful download of {$url}"
+	}
+}
+
+set table_with_ids GradesTable
+set ids_col IdNum
+if { ![doesColumnExists $ids_col $table_with_ids] } {
+	puts "something wrong with database: the column {$ids_col} does not exist in table {$table_with_ids}"
+	db close
+	exit
+}
+
+set ids [getAllIds "$ids_col" "$table_with_ids"]
+foreach id  $ids {
+	if { "$id" eq "" } {
+		# invalid/useless id
+		continue
+	}
+	cachePhotoForId $id
+}
+
+db close
+
+# vim: ts=2 sw=2 foldmethod=indent: