Add file browser to FLEX.

Based on existing code in Flipboard written by @edog1203 with contributions from others. The file browser allows users to explore the file system within the application’s sandbox and view text files, images, video, etc.

Classes/Global State Explorers/FLEXFileBrowserTableViewController.h

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+//
+//  FLEXFileBrowserTableViewController.h
+//  Flipboard
+//
+//  Created by Ryan Olson on 6/9/14.
+//  Based on previous work by Evan Doll
+//
+
+#import <UIKit/UIKit.h>
+
+@interface FLEXFileBrowserTableViewController : UITableViewController
+
+- (id)initWithPath:(NSString *)path;
+
+@end

Classes/Global State Explorers/FLEXFileBrowserTableViewController.m

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+//
+//  FLEXFileBrowserTableViewController.m
+//  Flipboard
+//
+//  Created by Ryan Olson on 6/9/14.
+//
+//
+
+#import "FLEXFileBrowserTableViewController.h"
+#import "FLEXUtility.h"
+#import "FLEXWebViewController.h"
+
+@interface FLEXFileBrowserTableViewController ()
+
+@property (nonatomic, copy) NSString *path;
+@property (nonatomic, copy) NSArray *childPaths;
+@property (nonatomic, strong) NSNumber *recursiveSize;
+
+@end
+
+@implementation FLEXFileBrowserTableViewController
+
+- (id)initWithStyle:(UITableViewStyle)style
+{
+    return [self initWithPath:NSHomeDirectory()];
+}
+
+- (id)initWithPath:(NSString *)path
+{
+    self = [super initWithStyle:UITableViewStyleGrouped];
+    if (self) {
+        self.path = path;
+        self.title = [path lastPathComponent];
+        
+        FLEXFileBrowserTableViewController *__weak weakSelf = self;
+        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+            NSFileManager *fileManager = [[NSFileManager alloc] init];
+            NSDictionary *attributes = [fileManager attributesOfItemAtPath:path error:NULL];
+            uint64_t totalSize = [attributes fileSize];
+            
+            for (NSString *fileName in [fileManager enumeratorAtPath:path]) {
+                attributes = [fileManager attributesOfItemAtPath:[path stringByAppendingPathComponent:fileName] error:NULL];
+                totalSize += [attributes fileSize];
+                
+                // Bail if the interested view controller has gone away.
+                if (!weakSelf) {
+                    return;
+                }
+            }
+            
+            dispatch_async(dispatch_get_main_queue(), ^{
+                weakSelf.recursiveSize = @(totalSize);
+                [weakSelf.tableView reloadData];
+            });
+        });
+        
+        self.childPaths = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:NULL];
+    }
+    return self;
+}
+
+- (BOOL)prefersStatusBarHidden
+{
+    return YES;
+}
+
+#pragma mark - Table view data source
+
+- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
+{
+    return 1;
+}
+
+- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
+{
+    return [self.childPaths count];
+}
+
+- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
+{
+    NSString *sizeString = nil;
+    if (!self.recursiveSize) {
+        sizeString = @"Computing size…";
+    } else {
+        sizeString = [NSByteCountFormatter stringFromByteCount:[self.recursiveSize longLongValue] countStyle:NSByteCountFormatterCountStyleFile];
+    }
+    
+    return [NSString stringWithFormat:@"%lu files (%@)", (unsigned long)[self.childPaths count], sizeString];
+}
+
+- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
+{
+    NSString *subpath = [self.childPaths objectAtIndex:indexPath.row];
+    NSString *fullPath = [self.path stringByAppendingPathComponent:subpath];
+    NSDictionary *attributes = [[NSFileManager defaultManager] attributesOfItemAtPath:fullPath error:NULL];
+    BOOL isDirectory = [[attributes fileType] isEqual:NSFileTypeDirectory];
+    NSString *subtitle = nil;
+    if (isDirectory) {
+        NSUInteger count = [[[NSFileManager defaultManager] contentsOfDirectoryAtPath:fullPath error:NULL] count];
+        subtitle = [NSString stringWithFormat:@"%lu file%@", (unsigned long)count, (count == 1 ? @"" : @"s")];
+    } else {
+        NSString *sizeString = [NSByteCountFormatter stringFromByteCount:[attributes fileSize] countStyle:NSByteCountFormatterCountStyleFile];
+        subtitle = [NSString stringWithFormat:@"%@ - %@", sizeString, [attributes fileModificationDate]];
+    }
+    
+    static NSString *cellIdentifier = @"Cell";
+    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
+    if (!cell) {
+        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
+        cell.textLabel.font = [FLEXUtility defaultTableViewCellLabelFont];
+        cell.detailTextLabel.font = [FLEXUtility defaultTableViewCellLabelFont];
+        cell.detailTextLabel.textColor = [UIColor grayColor];
+        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
+    }
+    cell.textLabel.text = [subpath lastPathComponent];
+    cell.detailTextLabel.text = subtitle;
+    
+    return cell;
+}
+
+- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
+{
+    NSString *subpath = [self.childPaths objectAtIndex:indexPath.row];
+    NSString *fullPath = [self.path stringByAppendingPathComponent:subpath];
+    BOOL isDirectory = NO;
+    BOOL stillExists = [[NSFileManager defaultManager] fileExistsAtPath:fullPath isDirectory:&isDirectory];
+    if (stillExists) {
+        UIViewController *drillInViewController = nil;
+        if (isDirectory) {
+            drillInViewController = [[[self class] alloc] initWithPath:fullPath];
+        } else {
+            // Special case keyed archives, json, and plists to get more readable data.
+            NSString *prettyString = nil;
+            if ([[subpath pathExtension] isEqual:@"archive"]) {
+                prettyString = [[NSKeyedUnarchiver unarchiveObjectWithFile:fullPath] description];
+            } else if ([[subpath pathExtension] isEqualToString:@"json"]) {
+                NSData *fileData = [NSData dataWithContentsOfFile:fullPath];
+                id jsonObject = [NSJSONSerialization JSONObjectWithData:fileData options:0 error:NULL];
+                prettyString = [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:jsonObject options:NSJSONWritingPrettyPrinted error:NULL] encoding:NSUTF8StringEncoding];
+            } else if ([[subpath pathExtension] isEqualToString:@"plist"]) {
+                NSData *fileData = [NSData dataWithContentsOfFile:fullPath];
+                prettyString = [[NSPropertyListSerialization propertyListWithData:fileData options:0 format:NULL error:NULL] description];
+            }
+            
+            if ([prettyString length] > 0) {
+                drillInViewController = [[FLEXWebViewController alloc] initWithText:prettyString];
+            } else if ([FLEXWebViewController supportsPathExtension:[subpath pathExtension]]) {
+                drillInViewController = [[FLEXWebViewController alloc] initWithURL:[NSURL fileURLWithPath:fullPath]];
+            } else {
+                NSString *fileString = [NSString stringWithContentsOfFile:fullPath encoding:NSUTF8StringEncoding error:NULL];
+                if ([fileString length] > 0) {
+                    drillInViewController = [[FLEXWebViewController alloc] initWithText:fileString];
+                }
+            }
+        }
+        
+        if (drillInViewController) {
+            drillInViewController.title = [subpath lastPathComponent];
+            [self.navigationController pushViewController:drillInViewController animated:YES];
+        } else {
+            [self.tableView deselectRowAtIndexPath:indexPath animated:YES];
+        }
+    } else {
+        [[[UIAlertView alloc] initWithTitle:@"File Removed" message:@"The file at the specified path no longer exists." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
+    }
+}
+
+@end

Classes/Global State Explorers/FLEXWebViewController.h

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+//
+//  FLEXWebViewController.m
+//  Flipboard
+//
+//  Created by Ryan Olson on 6/10/14.
+//  Copyright (c) 2014 Flipboard. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+@interface FLEXWebViewController : UIViewController
+
+- (id)initWithURL:(NSURL *)url;
+- (id)initWithText:(NSString *)text;
+
++ (BOOL)supportsPathExtension:(NSString *)extension;
+
+@end

Classes/Global State Explorers/FLEXWebViewController.m

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+//
+//  FLEXWebViewController.m
+//  Flipboard
+//
+//  Created by Ryan Olson on 6/10/14.
+//  Copyright (c) 2014 Flipboard. All rights reserved.
+//
+
+#import "FLEXWebViewController.h"
+#import "FLEXUtility.h"
+
+@interface FLEXWebViewController () <UIWebViewDelegate>
+
+@property (nonatomic, strong) UIWebView *webView;
+@property (nonatomic, strong) NSString *originalText;
+
+@end
+
+@implementation FLEXWebViewController
+
+- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
+{
+    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
+    if (self) {
+        self.webView = [[UIWebView alloc] init];
+        self.webView.delegate = self;
+        self.webView.dataDetectorTypes = UIDataDetectorTypeLink;
+        self.webView.scalesPageToFit = YES;
+    }
+    return self;
+}
+
+- (id)initWithText:(NSString *)text
+{
+    self = [self initWithNibName:nil bundle:nil];
+    if (self) {
+        self.originalText = text;
+        NSString *htmlString = [NSString stringWithFormat:@"<pre>%@</pre>", [FLEXUtility stringByEscapingHTMLEntitiesInString:text]];
+        [self.webView loadHTMLString:htmlString baseURL:nil];
+    }
+    return self;
+}
+
+- (id)initWithURL:(NSURL *)url
+{
+    self = [self initWithNibName:nil bundle:nil];
+    if (self) {
+        NSURLRequest *request = [NSURLRequest requestWithURL:url];
+        [self.webView loadRequest:request];
+    }
+    return self;
+}
+
+- (void)viewDidLoad
+{
+    [super viewDidLoad];
+    
+    [self.view addSubview:self.webView];
+    self.webView.frame = self.view.bounds;
+    self.webView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
+    
+    if ([self.originalText length] > 0) {
+        self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Copy to Clipboard" style:UIBarButtonItemStylePlain target:self action:@selector(copyButtonTapped:)];
+    }
+}
+
+- (BOOL)prefersStatusBarHidden
+{
+    return YES;
+}
+
+- (void)copyButtonTapped:(id)sender
+{
+    [[UIPasteboard generalPasteboard] setString:self.originalText];
+}
+
+
+#pragma mark - UIWebView Delegate
+
+- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
+{
+    BOOL shouldStart = NO;
+    if (navigationType == UIWebViewNavigationTypeOther) {
+        // Allow the initial load
+        shouldStart = YES;
+    } else {
+        // For clicked links, push another web view controller onto the navigation stack so that hitting the back button works as expected.
+        // Don't allow the current web view do handle the navigation.
+        FLEXWebViewController *webVC = [[[self class] alloc] initWithURL:[request URL]];
+        [self.navigationController pushViewController:webVC animated:YES];
+    }
+    return shouldStart;
+}
+
+
+#pragma mark - Class Helpers
+
++ (BOOL)supportsPathExtension:(NSString *)extension
+{
+    BOOL supported = NO;
+    NSSet *supportedExtensions = [self webViewSupportedPathExtensions];
+    if ([supportedExtensions containsObject:[extension lowercaseString]]) {
+        supported = YES;
+    }
+    return supported;
+}
+
++ (NSSet *)webViewSupportedPathExtensions
+{
+    static NSSet *pathExtenstions = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        // Note that this is not exhaustive, but all these extensions should work well in the web view.
+        // See https://developer.apple.com/library/ios/documentation/AppleApplications/Reference/SafariWebContent/CreatingContentforSafarioniPhone/CreatingContentforSafarioniPhone.html#//apple_ref/doc/uid/TP40006482-SW7
+        pathExtenstions = [NSSet setWithArray:@[@"jpg", @"jpeg", @"png", @"gif", @"pdf", @"svg", @"tiff", @"3gp", @"3gpp", @"3g2",
+                                                @"3gp2", @"aiff", @"aif", @"aifc", @"cdda", @"amr", @"mp3", @"swa", @"mp4", @"mpeg",
+                                                @"mpg", @"mp3", @"wav", @"bwf", @"m4a", @"m4b", @"m4p", @"mov", @"qt", @"mqv", @"m4v"]];
+        
+    });
+    return pathExtenstions;
+}
+
+@end