PdfReader.razor.cs

// Copyright (c) Argo Zhang (argo@163.com). All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
// Website: https://www.blazor.zone or https://argozhang.github.io/

using Microsoft.AspNetCore.Components;
using System.Web;
using UAParser;

namespace BootstrapBlazor.Components;

/// <summary>
/// Blazor Pdf Reader PDF阅读器 组件 
/// </summary>
public partial class PdfReader : IAsyncDisposable
{
    [Inject]
    [NotNull]
    private IJSRuntime? JSRuntime { get; set; }

    [NotNull]
    private IJSObjectReference? Module { get; set; }

    /// <summary>
    /// UI界面元素的引用对象
    /// </summary>
    private ElementReference Element { get; set; }

    /// <summary>
    /// 获得/设置 用于渲染的文件流,为空则用 FileName 参数读取文件
    /// </summary>
    [Parameter]
    public Stream? Stream { get; set; }

    private byte[]? streamCache { get; set; }

    /// <summary>
    /// 获得/设置 PDF文件URL, 默认 http 开头自动使用流模式读取
    /// </summary>
    [Parameter]
    public string? FileName { get; set; }
    string? fileNameCache { get; set; }

    /// <summary>
    /// 获得/设置 使用流化模式,可跨域读取文件. 默认为 false
    /// </summary>
    [Parameter]
    public bool StreamMode { get; set; }

    /// <summary>
    /// 获得/设置 宽 单位(px|%) 默认 100%
    /// </summary>
    [Parameter]
    public string Width { get; set; } = "100%";

    /// <summary>
    /// 获得/设置 高 单位(px|%) 默认 500px
    /// </summary>
    [Parameter]
    public string Height { get; set; } = "700px";

    /// <summary>
    /// 获得/设置 组件外观 Css Style
    /// </summary>
    [Parameter]
    public string? StyleString { get; set; }

    /// <summary>
    /// 获得/设置 页码
    /// </summary> 
    [Parameter]
    public int Page { get; set; } = 1;

    /// <summary>
    /// 获得/设置 显示导航窗格
    /// </summary> 
    [Parameter]
    public bool Navpanes { get; set; } = true;

    /// <summary>
    /// 获得/设置 显示工具栏
    /// </summary> 
    [Parameter]
    public bool Toolbar { get; set; } = true;

    /// <summary>
    /// 获得/设置 显示状态栏
    /// </summary> 
    [Parameter]
    public bool Statusbar { get; set; } = true;

    /// <summary>
    /// [已过时,使用 Zoom 代替] 获得/设置 视图模式, 
    /// </summary>
    [Parameter]
    [Obsolete]
    public string? View { get; set; }

    /// <summary>
    /// 获得/设置 页面模式
    /// </summary>
    [Parameter]
    public EnumPageMode? Pagemode { get; set; } = EnumPageMode.Thumbs;

    /// <summary>
    /// 获得/设置 查询关键字
    /// </summary>
    [Parameter]
    public string? Search { get; set; }

    /// <summary>
    /// 获得/设置 缩放模式 默认为 自动
    /// </summary>
    [Parameter]
    public EnumZoomMode? Zoom { get; set; } = EnumZoomMode.Auto;

    /// <summary>
    /// 获得/设置 浏览器路径
    /// </summary> 
    [Parameter]
    public string ViewerBase { get; set; } = "/_content/BootstrapBlazor.PdfReader/web/viewer.html";

    /// <summary>
    /// 获得/设置 禁用复制/打印/下载
    /// </summary> 
    [Parameter]
    public bool ReadOnly { get; set; }

    /// <summary>
    /// 获得/设置 水印内容
    /// </summary> 
    [Parameter]
    public string? Watermark { get; set; }

    /// <summary>
    /// 获得/设置 水印内容仅在全屏演示状态显示
    /// </summary> 
    [Parameter]
    public bool WatermarkDemoModeOnly { get; set; }

    /// <summary>
    /// Debug
    /// </summary>
    [Parameter]
    public bool Debug { get; set; }

    /// <summary>
    /// 获得/设置 'http' 开头自动使用流模式读取
    /// </summary> 
    [Parameter]
    public bool AutoStreamMode { get; set; } = true;

    /// <summary>
    /// 获得/设置 读取本地文件路径
    /// </summary> 
    [Parameter]
    public string? LocalFileName { get; set; }
    string? localFileNameCache { get; set; }

    /// <summary>
    /// 获得/设置 兼容模式,兼容旧版浏览器 默认为 false
    /// </summary> 
    [Parameter]
    public bool CompatibilityMode { get; set; }

    /// <summary>
    /// 获得/设置 兼容模式,兼容旧版不支持es5的浏览器 默认为 false
    /// <para>Compatible with older browsers that do not support ES5</para>
    /// </summary> 
    [Parameter]
    public bool CompatibilityNoneES5 { get; set; }

    string? ErrorMessage { get; set; }

    private string? Url { get; set; }

    private string? UrlDebug { get; set; }

    private UAParser.ClientInfo? ClientInfo { get; set; }

    /// <summary>
    /// <inheritdoc/>
    /// </summary>
    /// <param name="firstRender"></param>
    /// <returns></returns>
    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            Module = await JSRuntime.InvokeAsync<IJSObjectReference>("import", "./_content/BootstrapBlazor.PdfReader/app.js" + "?v=" + System.Reflection.Assembly.GetExecutingAssembly().GetName().Version);
            var userAgent = await Module!.InvokeAsync<string>("getUserAgent");
            var parser = Parser.GetDefault();
            ClientInfo = parser.Parse(userAgent);
            if (!WatermarkDemoModeOnly)
            { 
                WatermarkDemoModeOnly = await Module.InvokeAsync<bool>("getGlobalWatermark");
            }
            await Refresh();
        }
    }

    /// <summary>
    /// 刷新组件
    /// </summary>
    /// <returns></returns>
    public virtual async Task Refresh() => await Refresh(null, null, null, null);

    /// <summary>
    /// 跳转页码
    /// </summary>
    /// <param name="page">页码</param>
    /// <returns></returns>
    public virtual async Task NavigateToPage(int page) => await Refresh(page: page);

    /// <summary>
    /// 刷新组件
    /// </summary>
    /// <param name="page">页码</param>
    /// <returns></returns>
    public virtual async Task Refresh(int page) => await Refresh(page: page);

    /// <summary>
    /// 刷新组件
    /// </summary>
    /// <param name="search">查询关键字</param>
    /// <param name="page">页码</param>
    /// <param name="pagemode">页面模式</param>
    /// <param name="zoom">缩放模式</param>
    /// <param name="readOnly">禁用复制/打印/下载</param>
    /// <param name="watermark">水印内容</param>
    /// <param name="compatibilityMode">兼容模式,兼容旧版浏览器</param>
    /// <returns></returns>
    public virtual async Task Refresh(string? search = null, int? page = null, EnumPageMode? pagemode = null, EnumZoomMode? zoom = null, bool? readOnly = null, string? watermark = null, bool? compatibilityMode = null)
    {
        ErrorMessage = null;
        try
        {
            Search = search ?? Search;
            Page = page ?? Page;
            Pagemode = pagemode ?? Pagemode;
            Zoom = zoom ?? Zoom;
            ReadOnly = readOnly ?? ReadOnly;
            Watermark = watermark ?? Watermark;
            CompatibilityMode = compatibilityMode ?? CompatibilityMode;

            if (CompatibilityNoneES5 || (ClientInfo != null && ClientInfo.UA.Family.StartsWith("Chrome") == true && Convert.ToInt32(ClientInfo.UA.Major) < 97))
            {
                CompatibilityMode = true;
                ViewerBase = "/_content/BootstrapBlazor.PdfReader/compat/web/viewer.html";
            }
            else if (CompatibilityMode || (ClientInfo != null && ClientInfo.UA.Family.StartsWith("Chrome") == true && Convert.ToInt32(ClientInfo.UA.Major) < 109))
            {
                ViewerBase = "/_content/BootstrapBlazor.PdfReader/2.6.347/web/viewer.html";
            }
            else if (ReadOnly || readOnly != null)
            {
                ViewerBase = ReadOnly ? "/_content/BootstrapBlazor.PdfReader/web/viewerlimit.html" : "/_content/BootstrapBlazor.PdfReader/web/viewer.html";
            }

            if (Stream != null)
            {
                await ShowPdf(Stream);
            }
            else if (!string.IsNullOrEmpty(LocalFileName) && File.Exists(LocalFileName))
            {
                var streamLocal = new FileStream(LocalFileName, FileMode.Open, FileAccess.Read);
                if (streamLocal != null)
                {
                    await ShowPdf(streamLocal, fileNameCache != localFileNameCache, true);
                    localFileNameCache = LocalFileName;
                }
                else
                {
                    ErrorMessage = "No data";
                }
            }
            else if (!string.IsNullOrEmpty(FileName) && (StreamMode || (AutoStreamMode && FileName.StartsWith("http"))))
            {
                var client = new HttpClient();
                var stream = await client.GetStreamAsync(FileName);
                if (stream != null)
                {
                    await ShowPdf(stream, fileNameCache != FileName);
                    fileNameCache = FileName;
                }
                else
                {
                    ErrorMessage = "No data";
                }
            }
            else
            {
                Url = GenUrl();
            }

        }
        catch (Exception e)
        {
            ErrorMessage = e.Message;
        }
        StateHasChanged();

    }

    private string GenUrl(bool filemode = true) => $"{ViewerBase}?file={(filemode ? HttpUtility.UrlEncode(FileName) : "(1)")}#page={Page}&navpanes={(Navpanes ? 0 : 1)}&toolbar={(Toolbar ? 0 : 1)}&statusbar={(Statusbar ? 0 : 1)}&pagemode={(Pagemode ?? EnumPageMode.Thumbs).ToString().ToLower()}&search={Search}" + (Zoom != null ? $"&zoom={Zoom.GetEnumName()}" : "") + (Watermark != null ? $"&wm={Watermark}" : "") + (WatermarkDemoModeOnly ? $"&wmonlydemo=true" : "");


    /// <summary>
    /// 打开 LocalFileName
    /// </summary>
    /// <param name="localFileName"></param> 
    /// <returns></returns>
    public virtual async Task ShowPdf(string localFileName)
    {
        LocalFileName = localFileName;
        await Refresh();
    }


    /// <summary>
    /// 打开 stream
    /// </summary>
    /// <param name="stream"></param>
    /// <param name="forceLoad">default true</param>
    /// <param name="islocalFile"></param>
    /// <returns></returns>
    public virtual async Task ShowPdf(Stream stream, bool forceLoad = true, bool islocalFile = false)
    {
        if (Module == null)
        {
            Stream = stream;
        }
        else if (islocalFile)
        {
            if (forceLoad)
            {
                streamCache = new byte[stream.Length];
                stream.Read(streamCache, 0, (int)stream.Length);
            }
            if (streamCache == null)
            {
                streamCache = new byte[stream.Length];
                stream.Read(streamCache, 0, (int)stream.Length);
            }
            if (streamCache != null)
            {
                Url = null;
                var url = GenUrl(false);
                UrlDebug = url;
                using var streamRef = new DotNetStreamReference(new MemoryStream(streamCache));
                await Module!.InvokeVoidAsync("showPdf", url, Element, streamRef);
            }
        }
        else
        {
            Url = null;
            var url = GenUrl(false);
            UrlDebug = url;
            using var streamRef = new DotNetStreamReference(stream);
            await Module!.InvokeVoidAsync("showPdf", url, Element, streamRef);
        }
    }

    /// <summary>
    /// <inheritdoc/>
    /// </summary>
    /// <returns></returns>
    public async ValueTask DisposeAsync()
    {
        if (Module is not null)
        {
            try
            {
                await Module.DisposeAsync();
            }
            catch { }
        }
        GC.SuppressFinalize(this);
    }


}