SharpCorePDF.Application 1.0.0-preview.1

<p align="center"> <img src="https://raw.githubusercontent.com/MPCoreDeveloper/SharpCorePDF/main/Logo.jpg" alt="SharpCorePDF" width="260" /> </p> <p align="center"> <a href="https://www.nuget.org/packages/SharpCorePDF.DependencyInjection"> <img src="https://img.shields.io/nuget/vpre/SharpCorePDF.DependencyInjection?label=nuget.org" alt="nuget.org version" /> </a> <a href="https://github.com/MPCoreDeveloper/SharpCorePDF/blob/main/LICENSE"> <img src="https://img.shields.io/badge/licence-MIT-blue" alt="licence: MIT" /> </a> </p>

SharpCorePDF

A dependency-injection first, domain-driven PDF library for .NET 10 and .NET 11, built around one capability done properly: merging PDF documents — whole documents, selected pages, in any order.

Every PDF byte is read and written by this library. There is no dependency on a third-party PDF engine, no native binary and no licence to accept: the reader, the writer and the merge engine are part of the package, and they are covered by tests against real-world documents and validated with independent implementations (qpdf via pikepdf, and pypdf).

What it does

using SharpCorePDF.Domain.Aggregates;
using SharpCorePDF.Domain.Ports;
using SharpCorePDF.Infrastructure.Extensions;

var plan = MergePlan.Create()
    .AddFile(@"C:\reports\summary.pdf")                // every page
    .AddFile(@"C:\reports\appendix.pdf", pages: "1-3") // one-based, "1,3-5,8-"
    .AddFile(@"C:\reports\annex.pdf", pages: "3,1");   // in this order

await merger.MergeToFileAsync(plan, @"C:\reports\combined.pdf");

• Page selections in the notation people write: 5, 2-7, 3-, -4, comma separated, in the order they are given. Page numbers are always one-based.
• Everything of every source travels with its pages: content streams, images, fonts, resources, annotations, bookmarks and form widgets. Stream bytes are copied verbatim — nothing is re-compressed.
• One flat page tree in the result, with the inheritable page attributes (Resources, MediaBox, CropBox, Rotate) materialised onto each page, which is what makes partial selections and reordering possible.
• Bookmarks of every source are merged into one tree whose top level items follow the source order.
• Document level features — viewer preferences, page layout and mode, the interactive form, named destinations, embedded files, page labels, XMP metadata — are carried over from the primary source, because they cannot sensibly exist twice in one document.
• Document information is taken from the primary source, merged from all sources, or suppressed; an explicit override always wins. Fix ModificationDate and the output is reproducible byte for byte.
• Diagnostics instead of surprises: damaged cross-reference tables are rebuilt by scanning the file, unselected pages that something still points at are folded onto a page that exists, and anything the merge had to change is reported in MergeResult.Warnings.

Getting it into a project

The dependency injection package wires everything behind its ports:

using SharpCorePDF.DependencyInjection;
using SharpCorePDF.Domain.Ports;

services.AddSharpCorePDF();                                      // default engine options
services.AddSharpCorePDF(PdfEngineOptions.Default with { ... });  // explicit options
services.AddSharpCorePDF(configuration);                         // from the "SharpCorePDF" section
services.AddSharpCorePDF(configuration, "My:Pdf:Section");       // from a section of your choosing

var merger = provider.GetRequiredService<IPdfMerger>();
var inspector = provider.GetRequiredService<IPdfInspector>();

Every package targets net10.0 and net11.0 and carries both legs: NuGet hands a net10.0 app the lib/net10.0 assembly and a net11.0 app the lib/net11.0 one, with exactly the same API on both. Nothing else is supported yet — there is no netstandard2.0 or net8.0 leg, so a project that targets .NET 8 or .NET 9 cannot install these packages.

IPdfInspector.InspectAsync describes a document — version, page count and sizes, rotation, metadata, bookmarks, embedded files, form presence, warnings — and reports an encrypted document instead of throwing, so a caller can decide what to do before merging anything.

The package to install is SharpCorePDF.DependencyInjection: it depends on the other three, and its AddSharpCorePDF() call is the whole wiring. The version is still a preview, so --prerelease is required until 1.0.0 ships:

dotnet add package SharpCorePDF.DependencyInjection --prerelease

The XML documentation ships inside the packages, so every public type and member is described in IntelliSense without leaving the editor.

To work against this source tree instead of the feed, reference the project (dotnet add reference .\src\SharpCorePDF.DependencyInjection\SharpCorePDF.DependencyInjection.csproj), or pack all four into a local feed and install them from there:

dotnet pack .\SharpCorePDF.slnx -c Release -o $env:TEMP\SharpCorePDF-feed
dotnet nuget add source $env:TEMP\SharpCorePDF-feed --name SharpCorePDF
dotnet add package SharpCorePDF.DependencyInjection --prerelease

Every package carries the logo as its package icon and embeds this README, so the page a feed shows for it is the introduction you are reading. nuget.org renders images only from a list of trusted hosts and cannot resolve relative paths, which is why the logo and the links in this file are absolute URLs.

Examples

examples/SharpCorePDF.Examples is a console app with eight runnable examples. Every snippet on this page is code that compiles and executes there:

dotnet run --project .\examples\SharpCorePDF.Examples -c Release          # all of them
dotnet run --project .\examples\SharpCorePDF.Examples -- select-pages    # one of them
dotnet run --project .\examples\SharpCorePDF.Examples -- errors options  # several, in this order

The examples generate the documents they merge, so nothing else is needed to run them, and they leave the results in a folder under the temporary directory for you to open. examples/README.md walks through each one.

How it is put together

Four packages, one per layer. Each name links to its page on nuget.org.

The domain and the application layer know nothing about PDF syntax; the engine implements their ports. That is what keeps the merge rules testable without a single PDF file, and what would let a different engine be swapped in.

Why the engine looks the way it does

• A source is read into memory once and its objects are resolved on demand, so a damaged object that no page needs never stops a merge.
• Objects are copied in two phases: first every reachable object is reserved a target number, then the bodies are written. That is what makes the cyclic graphs real files contain — a form field that points at its widget which points back at the field — terminate.
• Only objects reachable from the kept pages and features are copied, so the result does not inherit the dead weight of its sources.
• Object streams and cross-reference streams are decoded (their contents have to be understood); every other stream is copied byte for byte. The result uses a classic cross-reference table, which every reader in existence supports.

Known limits (deliberate, for version 1)

• Encrypted documents are refused with PdfEncryptionException; no decryption is attempted, so PdfDocumentInfo.RequiresPassword is always false — the engine cannot know whether an empty user password would have opened the file.
• Named destinations are merged from the primary source only. A bookmark of another source that used a named destination keeps its title and loses its destination, and the merge says so in its warnings.
• The result is written as PDF 1.4 – 2.0 with a classic cross-reference table and no object streams; MergeOutputOptions.TargetVersion (default PDF 1.7) decides the header.
• A reference to a page that was not selected is folded onto the first page that source contributed, so a link stays valid instead of dangling.
• A bookmark that is stored inline in the page tree (not as an indirect object) cannot be referenced and is skipped, with a warning.

Building and testing

# Everything at once, through the solution: the four packages, the tests,
# the examples and the measurement harness.
dotnet build .\SharpCorePDF.slnx -c Release
dotnet test  .\SharpCorePDF.slnx                      # 53 tests on net10.0, 53 on net11.0
dotnet run --project .\examples\SharpCorePDF.Examples -c Release

# Or one project at a time:
dotnet build .\src\SharpCorePDF.DependencyInjection\SharpCorePDF.DependencyInjection.csproj

# The test project must build an app host, which the RID-less net10.0 leg of some SDK builds skips:
dotnet test .\tests\SharpCorePDF.Tests\SharpCorePDF.Tests.csproj -p:TargetFramework=net11.0
dotnet test .\tests\SharpCorePDF.Tests\SharpCorePDF.Tests.csproj -p:TargetFramework=net10.0 -r win-x64

The tests cover the domain invariants, the serialisation details, the reader against a real-world document, a document that uses object streams and cross-reference streams, a document with bookmarks, page labels, annotations and a rotated page, an encrypted document, and the whole merge path through the container.

Measuring what a merge costs

dotnet run -c Release --project .\tools\SharpCorePDF.Measure
dotnet run -c Release --project .\tools\SharpCorePDF.Measure -- --single large

# GC mode is part of the measurement, and server mode is the deployment envelope:
$env:DOTNET_gcServer = "1"; dotnet run -c Release --project .\tools\SharpCorePDF.Measure

The harness reports the bytes a merge allocates, its wall time, the same allocations as a multiple of the input, throughput, the heap still held after a full collection, and the bytes the merge wrote — that last column is a fingerprint, because two runs that write the same bytes ran the same merge. --single <all|large|one|half> samples the managed heap during one isolated merge, which is what "peak" means. The recorded numbers, and what they say about the performance and memory budgets, are in docs/measurements.md.

Validating the output with an independent implementation

uv run --with pikepdf python .\docs\tools\validate-pdf.py <file.pdf>
uv run --with pikepdf python .\docs\tools\make-fixtures.py .\tests\SharpCorePDF.Tests\Assets

validate-pdf.py runs qpdf --check, decodes every stream in the file, and prints the geometry, rotation and annotations of every page. It is the check that caught the one bug this library has had so far: a hexadecimal string written with name escapes, which qpdf rejected as damage.

Publishing

Packages go to nuget.org from .github/workflows/publish.yml, and no API key is stored anywhere. The workflow asks GitHub for an OIDC token, exchanges it with nuget.org for a temporary API key that lives for one hour, and pushes. nuget.org performs that exchange only when the token matches a trusted publishing policy for this repository, so the workflow can publish nothing until that policy exists.

The policy lives at nuget.org → your username → Trusted Publishing, and its fields are the ones the workflow's header comment records:

The Create form then asks which scopes the policy grants — pushing new packages, pushing new versions of existing packages and unlisting are offered separately — and which packages those scopes apply to. That box is the one the portal labels Glob Patterns and Packages (Separate by a new line), and it takes one glob or exact package ID per line:

SharpCorePDF.*

An empty box is refused with At least one valid glob pattern or package must be specified. A line may hold only *, letters, digits, _, . and -, which is why SharpCorePDF.* is accepted and why it covers all four packages here; four lines holding the four IDs cover the same ground. The temporary API key is scoped to the subjects written there, so a package that no subject matches cannot be pushed.

The policy is owned by a nuget.org user or organization and applies to every package that owner owns; its scopes decide whether it may publish new packages, new versions of existing ones, or both. The user: input the workflow passes to NuGet/login is that account's username, kept as the repository secret NUGET_USERNAME (settings → Secrets and variables → Actions).

Publishing then happens one of two ways:

• Actions → publish → Run workflow. With publish left false it stops after packing: both test legs run, every package is checked, and the packages are pushed into a throwaway local feed as a handshake. Set publish to true to carry on to nuget.org.
• Push a v* tag — git tag v1.0.0-preview.1 && git push origin v1.0.0-preview.1. The tag is a v followed by the exact <Version> in src/Directory.Build.props, prerelease suffix included, because a tagged run refuses to publish a version the tag does not name: v1.0.0 against the current 1.0.0-preview.1 fails the check instead of publishing.

Nothing reaches a feed until the packages pass that check: every .nupkg must carry both lib/net10.0 and lib/net11.0, which is the promise made in src/Directory.Build.props.

A version on nuget.org is immutable, so bump <Version> before publishing; --skip-duplicate makes a re-run of an already-published version a no-op instead of an error. Publishing from a workstation still means a long-lived API key, because the temporary ones exist only inside a CI run. GitHub Packages is a separate mechanism that does not use any of this: it wants a token with packages: write, either GITHUB_TOKEN inside a workflow or a personal access token from a workstation.

Feedback

Bugs, questions and feature requests go to the issue tracker. The most valuable report of all is a merge that produced a file something else cannot open: attach the sources if you can, and the warning list the merge returned, and it becomes a test.