1 files changed, 228 insertions, 0 deletions
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
new file mode 100644
index 00000000..f452202d
--- /dev/null
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
@@ -0,0 +1,228 @@
+package at.asit.pdfover.gui.bku.mobile;
+
+import java.lang.reflect.InvocationTargetException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import javax.annotation.CheckForNull;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import org.jsoup.Jsoup;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static at.asit.pdfover.commons.Constants.ISNOTNULL;
+
+public class ATrustParser {
+    private static final Logger log = LoggerFactory.getLogger(ATrustParser.class);
+
+    private static class ComponentParseFailed extends Exception {}
+
+    private static class TopLevelFormBlock {
+        protected @Nonnull org.jsoup.nodes.Document htmlDocument;
+        protected @Nonnull Map<String, String> formOptions;
+        protected TopLevelFormBlock(@Nonnull org.jsoup.nodes.Document d, @Nonnull Map<String,String> fO) { this.htmlDocument = d; this.formOptions = fO; }
+
+        protected void abortIfElementMissing(@Nonnull String selector) throws ComponentParseFailed {
+            if (this.htmlDocument.selectFirst(selector) != null) return;
+            log.debug("Tested for element {} -- not found.", selector);
+            throw new ComponentParseFailed();
+        }
+        protected @Nonnull String getAttributeEnsureNotNull(@Nonnull String selector, @Nonnull String attribute) throws ComponentParseFailed {
+            var elm = this.htmlDocument.selectFirst(selector);
+            if (elm == null) { log.warn("Expected element not found in response: {}", selector); throw new ComponentParseFailed(); }
+            if (!elm.hasAttr(attribute)) { log.warn("Element {} is missing expected attribute '{}'.", selector, attribute); throw new ComponentParseFailed(); }
+            return ISNOTNULL(elm.attr(attribute));
+        }
+        protected @Nonnull URI getURIAttributeEnsureNotNull(@Nonnull String selector, @Nonnull String attribute) throws ComponentParseFailed {
+            String value = getAttributeEnsureNotNull(selector, attribute);
+            try {
+                return new URI(value);
+            } catch (URISyntaxException e) {
+                if (attribute.startsWith("abs:"))
+                    attribute = ISNOTNULL(attribute.substring(4));
+                log.warn("Element {} attribute {} is '{}', could not be parsed as URI", selector, attribute, getAttributeEnsureNotNull(selector, attribute));
+                throw new ComponentParseFailed();
+            }
+        }
+    }
+
+    public static class UsernamePasswordBlock extends TopLevelFormBlock {
+        private @Nonnull String usernameKey;
+        private @Nonnull String passwordKey;
+
+        public void setUsernamePassword(String username, String password) {
+            formOptions.put(usernameKey, username); formOptions.put(passwordKey, password);
+        }
+
+        private UsernamePasswordBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            abortIfElementMissing("#handynummer");
+            this.usernameKey = getAttributeEnsureNotNull("#handynummer", "name");
+            this.passwordKey = getAttributeEnsureNotNull("#signaturpasswort", "name");
+            
+            /* remove unused submit buttons */
+            // TODO: we should generalize this somehow for input type="submit"
+            // TODO: do we maybe want to use the actual cancel button?
+            formOptions.remove(getAttributeEnsureNotNull("#Button_Cancel", "name"));
+            formOptions.remove(getAttributeEnsureNotNull("#Button_localBku", "name"));
+        }
+    }
+
+    public static class QRCodeBlock extends TopLevelFormBlock {
+        public @Nonnull URI qrCodeURI;
+
+        private QRCodeBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            abortIfElementMissing("#qrimage");
+            this.qrCodeURI = getURIAttributeEnsureNotNull("#qrimage", "abs:src");
+        }
+    }
+
+    public static class Fido2Block extends TopLevelFormBlock {
+        private @Nonnull String fidoOptions;
+        private @Nonnull String credentialResultKey;
+
+        public @Nonnull String getFIDOOptions() { return fidoOptions; }
+        public void setFIDOResult(String result) { formOptions.put(credentialResultKey, result); }
+
+        private Fido2Block(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            abortIfElementMissing("#fidoBlock");
+            this.fidoOptions = getAttributeEnsureNotNull("#credentialOptions", "value");
+            this.credentialResultKey = getAttributeEnsureNotNull("#credentialResult", "name");
+        }
+    }
+
+    public static class HTMLResult {
+        public final @Nonnull org.jsoup.nodes.Document htmlDocument;
+        public final @Nonnull URI formTarget;
+        public final @Nonnull Map<String, String> formOptions = new HashMap<>();
+
+        public @Nonnull Iterable<Map.Entry<String, String>> iterateFormOptions() { return ISNOTNULL(formOptions.entrySet()); }
+
+        /* optional mode switch links (any number may or may not be null) */
+        public final @CheckForNull URI fido2Link;
+
+        /* top-level blocks (exactly one is not null) */
+        public final @CheckForNull UsernamePasswordBlock usernamePasswordBlock;
+        public final @CheckForNull QRCodeBlock qrCodeBlock;
+        public final @CheckForNull Fido2Block fido2Block;
+
+        private void validate() {
+            Set<String> populated = new HashSet<>();
+
+            if (usernamePasswordBlock != null) populated.add("usernamePasswordBlock");
+            if (qrCodeBlock != null) populated.add("qrCodeBlock");
+            if (fido2Block != null) populated.add("fido2Block");
+
+            switch (populated.size()) {
+                case 0: log.error("Did not find any top-level blocks.\n{}", this.htmlDocument.toString()); break;
+                case 1: /* passed */ return;
+                default: log.error("Found too many top-level blocks: {}\n", String.join(", ", populated), this.htmlDocument.toString()); break;
+            }
+            throw new IllegalArgumentException("Unknown A-Trust page reached?");
+        }
+
+        private @Nullable URI getHrefIfExists(String selector) {
+            var elm = htmlDocument.selectFirst(selector);
+            if (elm == null) return null;
+
+            String url = elm.absUrl("href");
+            try {
+                return new URI(url);
+            } catch (Exception e) {
+                log.warn("Invalid {} href attribute: {} ({})", selector, elm.attr("href"), url);
+                return null;
+            }
+        }
+
+        /**
+         * tries to parse T using its constructor; if ComponentParseFailed is thrown, swallows it
+         */
+        private <T extends TopLevelFormBlock> @Nullable T TryParseMainBlock(Class<T> clazz) {
+            try {
+                return clazz.getDeclaredConstructor(org.jsoup.nodes.Document.class, Map.class).newInstance(this.htmlDocument, this.formOptions);
+            } catch (NoSuchMethodException | InstantiationException | IllegalAccessException | IllegalArgumentException | SecurityException e) {
+                log.error("Internal parser error; check your method signatures?", e);
+                return null;
+            } catch (InvocationTargetException wrappedE) {
+                Throwable e = wrappedE.getCause();
+                if (!(e instanceof ComponentParseFailed)) {
+                    if (e instanceof RuntimeException)
+                        throw (RuntimeException)e;
+                    log.warn("Unexpected parser failure.", e);
+                }
+                return null;
+            }
+        }
+
+        private HTMLResult(@Nonnull org.jsoup.nodes.Document htmlDocument) {
+            this.htmlDocument = htmlDocument;
+
+            var forms = htmlDocument.getElementsByTag("form");
+            if (forms.size() != 1) {
+                log.error("Found {} forms in A-Trust response document, expected 1. Document:\n{}", forms.size(), htmlDocument.toString());
+                throw new IllegalArgumentException("Failed to parse A-Trust response page");
+            }
+
+            var mainForm = ISNOTNULL(forms.first()); /* size check above */
+            String formAction = mainForm.absUrl("action");
+            try {
+                this.formTarget = new URI(formAction);
+            } catch (URISyntaxException e) {
+                log.error("Invalid form target in page: {} ({})", mainForm.attr("action"), formAction, e);
+                throw new IllegalArgumentException("Failed to parse A-Trust response page");
+            }
+
+            for (var input : mainForm.select("input")) {
+                String name = input.attr("name");
+                if (name.isEmpty())
+                    continue;
+                this.formOptions.put(name, input.attr("value"));
+            }
+
+            this.fido2Link = getHrefIfExists("#FidoButton");
+
+            this.usernamePasswordBlock = TryParseMainBlock(UsernamePasswordBlock.class);
+            this.qrCodeBlock = TryParseMainBlock(QRCodeBlock.class);
+            this.fido2Block = TryParseMainBlock(Fido2Block.class);
+            
+            validate();
+        }
+    }
+
+    public static class Result {
+        public final @CheckForNull String slResponse;
+        public final @CheckForNull HTMLResult html;
+
+        private Result(@Nonnull String slResponse) { this.slResponse = slResponse; this.html = null; }
+        private Result(@Nonnull org.jsoup.nodes.Document htmlDocument) { this.slResponse = null; this.html = new HTMLResult(htmlDocument); }
+    }
+
+    public static @Nonnull Result Parse(@Nonnull org.jsoup.nodes.Document htmlDocument) { return new Result(htmlDocument); }
+
+    public static @Nonnull Result Parse(URI baseURI, String contentType, @Nonnull String content) {
+        if (contentType.equals("text/html"))
+        {
+            var document = Jsoup.parse(content, baseURI.toASCIIString());
+            if (document == null)
+            {
+                log.error("Failed to parse HTML (document == null):\n{}", content);
+                throw new IllegalArgumentException("A-Trust parsing failed");
+            }
+            return Parse(document);
+        }
+
+        if (contentType.endsWith("/xml"))
+            return new Result(content);
+        
+        log.error("Unknown content-type \"{}\" from URI {}", contentType, baseURI.toString());
+        throw new IllegalArgumentException("Unknown A-Trust page reached?");
+    }
+}