Zig Requires Chilkat v11.7.0+

Extract Text from a Password-Protected PDF

See more PDF Text Extraction Examples

Demonstrates extracting text from a PDF that requires a password to open. The PDF loads without the password (its structure can be read), but the "text" operation fails because the content cannot be decrypted; "assess" reports that a password is required. With the UserPassword property set before loading, extraction works normally. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The PDF used in this example (user password: secret) is available at encrypted_user_password.pdf

    const pdf = try chilkat.Pdf.init();
    defer pdf.deinit();
    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    const json_out = try chilkat.JsonObject.init();
    defer json_out.deinit();

    // The PDF loads without its password: the file's structure is readable, so properties such as
    // NumPages and the security settings are available...
    pdf.loadFile("qa_data/pdf/encrypted_user_password.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    // ...but the content cannot be decrypted, so extracting text fails.
    pdf.extractText("text", json, json_out) catch {
        std.debug.print("Cannot extract: {s}\n", .{try pdf.getLastErrorText(alloc)});
    };

    // "assess" still works: it reports that a password is required and nothing else.
    pdf.extractText("assess", json, json_out) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("passwordRequired: {}\n", .{json_out.boolOf("quality.passwordRequired")});
    std.debug.print("rating: {s}\n", .{try json_out.stringOf(alloc, "quality.rating")});

    // Set the password and load again.
    pdf.setUserPassword("secret");
    pdf.loadFile("qa_data/pdf/encrypted_user_password.pdf") catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    pdf.extractText("text", json, json_out) catch {
        std.debug.print("{s}\n", .{try pdf.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("{s}\n", .{try json_out.stringOf(alloc, "text")});

    // Sample output:

    // Cannot extract: ChilkatLog:
    //   ExtractText:
    //     ...
    //       The PDF is encrypted and could not be opened (wrong or missing password); its text cannot be read.
    //     ...
    // passwordRequired: true
    // rating: none
    // Board Minutes (Confidential)
    //
    // The board met on 3 November 2026. Present: the chair, the treasurer and four members. The treasurer reported that spending for the season came in under budget.
    //
    // The meeting closed at 8.45 p.m.
}