86 lines
2.0 KiB
Markdown
86 lines
2.0 KiB
Markdown
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```c title="C"
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#include <kreuzberg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/*
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* The C FFI does not expose registration for custom DocumentExtractor
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* implementations. To add PDF-specific behaviour from C, register a
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* post-processor that runs only on PDF results and enriches them.
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*
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* The example below logs whenever the pipeline emits a PDF result, scoped
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* via the should_process hook so it never fires for other MIME types.
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*/
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static char *dup_cstr(const char *s) {
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size_t len = strlen(s);
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char *out = (char *)malloc(len + 1);
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if (out) {
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memcpy(out, s, len + 1);
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}
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return out;
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}
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static int32_t process_fn(
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const void *user_data,
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const char *result,
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const char *config,
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char **out_error
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) {
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(void)user_data;
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(void)config;
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(void)out_error;
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printf("pdf-metadata-extractor: serialised PDF result is %zu bytes\n", strlen(result));
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return 0;
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}
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static int32_t processing_stage_fn(
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const void *user_data,
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char **out_result
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) {
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(void)user_data;
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*out_result = dup_cstr("\"Late\"");
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return 0;
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}
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static int32_t should_process_fn(
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const void *user_data,
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const char *result,
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const char *config
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) {
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(void)user_data;
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(void)config;
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return strstr(result, "\"mime_type\":\"application/pdf\"") != NULL;
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}
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static int32_t priority_fn(const void *user_data) {
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(void)user_data;
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return 75;
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}
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int main(void) {
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KREUZBERGKreuzbergPostProcessorVTable vtable = {0};
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vtable.process = process_fn;
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vtable.processing_stage = processing_stage_fn;
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vtable.should_process = should_process_fn;
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vtable.priority = priority_fn;
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char *err = NULL;
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int32_t rc = kreuzberg_register_post_processor(
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"pdf-metadata-extractor",
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vtable,
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NULL,
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&err
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);
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if (rc != 0) {
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fprintf(stderr, "register post-processor failed: %s\n", err ? err : "(no detail)");
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kreuzberg_free_string(err);
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return 1;
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}
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printf("pdf-metadata-extractor registered\n");
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return 0;
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}
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```
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